JP6386700B2 - Structure, optical member, antireflection film, water repellent film, substrate for mass spectrometry, phase plate, method for producing structure, and method for producing antireflection film - Google Patents

Description

The present invention relates to a structure, an optical member, an antireflection film, and a water repellent film having a plurality of cones or protrusions, which are used in various applications such as antireflection materials, sensors, superhydrophobic materials, and superhydrophilic materials. The present invention relates to a substrate for mass spectrometry, a phase plate, a method for manufacturing a structure, and a method for manufacturing an antireflection film.

  Conventionally, a structure having a plurality of fine protrusions (hereinafter also referred to as a fine structure) on a scale smaller than the wavelength of light is a super water-repellent material, a super hydrophilic material, a battery material, an anti-friction material, an anti-reflection It is used as various structural materials.

Such a method for manufacturing a fine structure having a plurality of fine protrusions on a scale smaller than the wavelength of light can be roughly classified into the following three means.
1) A method of etching a workpiece after previously forming an object to be a mask on the workpiece.
(Consisting of mask placement process and etching process)
2) A method of etching a workpiece (etching process only).
3) A method in which a fine structure produced by 1), 2) or the like is used as a mold and transferred to a workpiece.

As a conventional manufacturing example having the mask arranging step and the etching step of 1), manufacturing in a semiconductor process centering on lithography has been attempted (Patent Document 3). In this method, a resist is applied to a substrate used for fine structure formation, exposure and development are performed through a photomask to obtain a mask pattern, and the mask pattern is transferred to the fine structure formation substrate by etching. Lithography technology has an advantage as a method capable of forming a precisely designed fine pattern (Patent Document 1).

  A technique for spontaneously forming the mask pattern without using a lithography technique has also been proposed. For example, a technique is disclosed in which a fine structure on a scale smaller than the wavelength of light can be easily produced by using fine particles arranged on a substrate, island-shaped metal thin film, or the like as a mask (Patent Literature). 2, 3).

  As a conventional manufacturing example consisting of “only the etching process” of 2), a phenomenon in which a needle-like shape is formed in the plasma etching (reactive ion etching) process of Si is known. (Non-Patent Document 1).

  As a conventional manufacturing example in which the fine structure of 3) is transferred as a mold, a method of transferring a fine protrusion shape to a photocurable resin or the like using a carbon material having a fine protrusion group formed using a plasma etching apparatus as a mold Etc. have been proposed. (Patent Document 4)

  In particular, when the shape of the convex portion in the fine structure is a cone shape, that is, the convex portion has a shape in which the area of a cross section perpendicular to the direction from the bottom to the tip is small along the direction. It can be used as a prevention film, a water repellent film, a superhydrophilic film, a substrate for mass spectrometry, a battery material, a friction prevention material, and the like.

  As a technique relating to the antireflection film, a technique for suppressing reflection by an optical interference effect by laminating a single layer or a plurality of layers of optical films having different refractive indexes with a thickness of several tens to several hundreds of nanometers, In order to form the optical film, a vacuum film formation method such as vapor deposition or sputtering, or a wet film formation method such as dip coating or spin coating is used. These general antireflection films are designed to have an excellent antireflection effect in a wavelength range in which a light incident angle is 0 degree and a wavelength range to be used is relatively narrow. However, an antireflection film used for a lens having a large aperture or a surface having a small curvature radius has an excellent antireflection function for a wide wavelength region and a good incident angle characteristic of a light beam. desired. As an anti-reflection measure with a wide wavelength range and good incident angle characteristics, a fine structure having a pitch shorter than the wavelength of the incident light (SWS; called Sub-Wavelength Structure or Moth-eye structure) is arranged. Is known (Patent Documents 5 and 6). In particular, when the microstructure has a sharpened structure, the volume occupied by the substance in the space gradually increases from the upper part to the lower part of the convex structure, and the refractive index changes sharply at the interface. As a result, the reflection is greatly reduced.

  It is known as a lotus leaf effect that a film having a microstructure having a plurality of convex portions on the surface exhibits high water repellency (Lotus Effect) (Patent Document 7, Non-Patent Document 2). It is possible to achieve super water repellency such that the contact angle of water droplets on the film surface exceeds 150 degrees by appropriately designing the conditions such as the shape, arrangement, and hydrophobic modification group of the protrusions. Such a film exhibiting super water repellency is expected to be applied to the surface coating of various optical members and building members.

  A film having a microstructure having a plurality of convex portions on its surface can also be used as a substrate for mass spectrometry. This is achieved by holding the material to be analyzed on a semiconductor thin film with a fine structure, ionizing the analyte without damaging the structure by laser or ion beam irradiation, and measuring its mass with high sensitivity. This is a technique for identifying components, and is known as surface-assisted mass spectrometry (SALDI-MS), which is similar to matrix-assisted mass spectrometry (Patent Document 8). The fine structure of the substrate surface is mainly associated with ionization. It has a role to prevent destruction of the specimen sample, and therefore it is necessary to have a size of about 10 nm. As a substrate used for this surface-assisted mass spectrometry, porous silicon produced by anodization of silicon is most common. In addition, as a material that can solve the problem of characteristic deterioration due to the decrease in the electrical conductivity of porous silicon due to oxidation in the air, it is made by coexistence of polyethylene glycol, an oxidation with a fine structure on the surface, which is produced by a sol-gel method A titanium thin film or the like has been proposed (Non-Patent Document 3). The titanium oxide thin film used for this purpose has micropores with a random shape of about 10 nanometers, and these micropores mainly have a role of preventing destruction of the specimen sample due to ionization.

JP 2001-272505 A JP 2000-71290 A JP 2009-215104 A JP 2010-186198 A JP 2005-157119 A JP 2006-10831 A JP 2010-188584 A US6288390B1

Adv. Mater. 2011, 23, 122-126 ACS NANO, 2012, 6, 3789-3799 Rapid Communication in Mass Spectrometry, 18, 1956-1964

However, there are several problems with the above-described conventional technology.
First, as a problem related to the fabrication of the fine structure having the plurality of convex portions, in the case of a method of etching a workpiece after previously forming a mask to be processed on the workpiece, a process for mask arrangement is performed. Since it is necessary, the manufacturing method is complicated and it may be difficult to manufacture at low cost. In addition, a manufacturing method using only etching without using a mask has a problem that applications are limited because there are very few applicable materials. For example, the black silicon and the carbon having a fine structure do not transmit visible light, and thus cannot be applied as an antireflection film to a member such as a lens. Therefore, there has been a demand for a technique for forming a plurality of fine cone-shaped convex portions on a wide range of materials, in particular, a transparent and stable material having a wide band gap without using a mask.

  In addition, in the conventionally reported water-repellent material film in which only the surface of each convex part is subjected to hydrophobic chemical modification, when the convex part shape is destroyed due to external force applied to the film surface, The cross-section exposed to the surface does not have a hydrophobic modifying group. As a result, there is a problem that a portion where water repellency is significantly deteriorated locally occurs in the film surface. For this reason, there has been a demand for a water-repellent material film that does not lower the water repellency even when a fracture surface occurs.

  In addition, the conventional substrate for mass spectrometry having a fine structure on the surface has a remarkably small size compared with the wavelength of the probe (laser light, etc.) used for ionization. However, there is a problem that the energy injected into the film is reduced, and as a result, ionization efficiency may be reduced. For this reason, there has been a demand for a technique capable of finely processing the form of the film so as to prevent reflection while maintaining a fine structure having a role of preventing destruction of the specimen sample accompanying ionization.

The present invention, substrate and, an optical member having a reflection preventing film on the surface of the substrate, the antireflection film have a plurality of cone portion on the surface, the cone portion mesostructure has, Ri structures der that the mesostructure having mesopores, the inside of the mesopores, and the presence of an inorganic material having a higher refractive index than the material of the wall portion forming the mesopores, the mesopores by the inorganic material is present in the interior, the difference between the refractive index of the the effective refractive index of the cone portion substrate is an optical member, wherein Rukoto reduced.

Another aspect of the present invention is an optical member having a base and an antireflection film present on the surface of the base, the antireflection film having a structure having a plurality of convex portions on the surface, The convex portion has a shape in which an area of a cross section when the convex portion is cut along a plane perpendicular to a direction from the bottom to the tip of the convex portion decreases along the direction. Having a mesostructure with pores;
A metal element is present at the tip of the convex portion, and when the length of the base of the convex portion is D and the height of the convex portion is H, H / D is 2.0 or more, and the meso In the hole, there is an inorganic material having a higher refractive index than the material of the wall part forming the mesopores, and the presence of the inorganic material in the mesopores results in effective refraction of the protrusions. The optical member is characterized in that the difference between the refractive index and the refractive index of the substrate is reduced.

Another aspect of the present invention is a method of forming a mesostructure having mesopores, and depositing a material having a material constituting a part of an etching chamber of a plasma etching apparatus without using a mask. Is etched, and the mesostructure has a shape in which the area of the cross section when the convex portion is cut along a surface perpendicular to the direction from the bottom to the tip is reduced along the direction. a method for producing a structure characterized by comprising the steps of several shapes formed, the convex portion.

  According to the present invention, an antireflection film having a high antireflection effect and a production method thereof, an optical member having an excellent antireflection effect, a water repellent film having an excellent water repellency, a substrate for mass spectrometry having a high detection sensitivity, a high accuracy A phase plate, a structure that can be used for the phase plate, and a manufacturing method thereof can be provided.

It is a schematic diagram for demonstrating the structure of the structure as described in 1st embodiment, and a preparation procedure. It is a schematic diagram of the structure described in the first embodiment, which is composed of a mesostructure having a structure in which cylindrical pores with a uniform diameter are regularly arranged. It is a schematic diagram of the structure comprised from several mesostructures from which a structure differs in 1st embodiment. It is a schematic diagram for demonstrating the state of introduction | transduction of the material in a mesopore. It is a schematic diagram for demonstrating arrangement | positioning of the some convex part in the structure as described in 1st embodiment. It is a schematic diagram for demonstrating the formation condition of the some convex part in the structure as described in 1st embodiment. It is a schematic diagram for demonstrating distribution in the surface of the some convex part in the structure as described in 1st embodiment. It is a schematic diagram for demonstrating the antireflection effect of the antireflection film as described in 4th embodiment, and a graph showing the change of the film refractive index accompanying the filling of the material in a mesopore. It is a figure which shows typically the depth direction analysis result of the amount of fluorine contained in the structure as described in 1st embodiment formed by performing plasma etching. It is a schematic diagram explaining the formation process of the structure as described in 4th Embodiment produced by performing plasma etching, forming the contamination derived from the member which comprises an etching apparatus in the shape of an island on the surface. In order to improve the H / D of the convex portion in the structure according to the first to third embodiments, the structure is formed by forming a material with a low etching rate on the surface and performing plasma etching in two stages. It is a schematic diagram explaining the formation process. It is a schematic diagram for demonstrating the process of producing the structure corresponding to the negative using the structure as described in 1st-3rd embodiment as a type | mold. In Example 7, it is a scanning electron micrograph of the structure comprised from the several fine cone-shaped convex part formed in the mesoporous silica film by plasma etching. It is a schematic diagram for demonstrating the apparatus structure of low pressure CVD used at the process of filling an inorganic material in a mesopore. In Example 12, it is a scanning electron micrograph of the structure comprised from the several fine cone-shaped convex part formed in the mesoporous silica film by plasma etching. In Example 12, it is a graph which shows the wavelength dependence of the reflectance of the produced anti-reflective film. In Example 20, it is a scanning electron micrograph of the structure comprised from the several fine cone-shaped convex part formed by the plasma etching on the quartz glass substrate. In Example 27, the mesoporous silica film is composed of a plurality of fine cone-shaped convex portions formed by performing plasma etching while depositing the contamination caused by the material constituting the etching apparatus in an island shape. Is a scanning electron micrograph of the structure. It is a schematic diagram for demonstrating the structure of the water-repellent film which has several uneven | corrugated shape from which a period differs in size. 2 is a photograph used to determine the contact angle of water on the water repellent film produced in Example 31. FIG. It is a schematic diagram for demonstrating the preparation process of the water-repellent film which has several uneven | corrugated shape from which the period and size described in Example 33 differ. It is a figure which shows the relationship between the refractive index n4 (nssub) of the member which implements reflection prevention, and the effective refractive index n3 (nfilm) of a fine structure, and the reflectance in the interface of both. FIG. 10 is a diagram showing a manufacturing process of Example 7. It is a schematic diagram of the structure which has a protective layer on the surface. It is a schematic diagram of the structure which has a protective layer on the surface. It is a figure explaining the shape where a part of tip of a cone was missing.

  Hereinafter, the present invention will be described in detail using examples of embodiments of the present invention.

<First embodiment>
First, a first embodiment of the present invention will be described.
The schematic diagram of the structure concerning this embodiment is shown in FIG. 1 (a) of FIG. 1 is a three-dimensional view of the structure, and 1 (b) is a cross-sectional view of the structure of 1 (a) taken along the line AA ′.

  The structure 11 of the present embodiment is a structure having a plurality of convex portions 12 on the surface, and the convex portions 12 have a meso structure, and the meso structure has a meso hole 13.

  The structure 11 has a mesostructure having (including) mesopores 13. As used herein, the mesopore refers to a pore having a diameter of 2 nm or more and less than 50 nm according to the definition of International Union of Pure and Applied Chemistry. The diameter of the pore means the diameter of the pore in the cross section where the cross-sectional area of the pore is the smallest. When the cross section of the pore is circular, it indicates the diameter, and the shape of the cross section is a polygon. In some cases, it refers to the maximum length of the diagonal line. When the cross-sectional shape is indefinite, the maximum diameter in the cross-sectional shape is defined as the pore diameter. The mesostructure refers to a structure in which the mesopores are arranged in a matrix (hereinafter also referred to as a wall portion) made of a material that forms pore walls. As will be described later, the mesopores may have voids (hollow) inside, and organic or inorganic materials may exist inside. Here, in the present invention and the present specification, the structure in the case where the mesopores are hollow is called a mesoporous material. The porosity of the mesoporous material is preferably 20% or more and 80% or less. Needless to say, the porosity of the mesoporous material is in the range of 20% to 80% and the porosity is in the range of 30% to 65%.

  The structure 11 of the present embodiment has a plurality of convex portions 12 as shown in FIG. The convex portion 12 has a shape in which the area of a cross section obtained by cutting the convex portion 12 along a plane 19 perpendicular to the direction 18 from the bottom portion 16 toward the tip end 17 decreases along the direction 18 (in other words, from the bottom portion 16 toward the tip end 17. The cross-sectional area perpendicular to the direction is reduced along the direction). In addition, when the hollow part which makes a part of mesopore exists in the cross section which cut | disconnected the convex part by the surface 19, the area of a hollow part shall be included in the area of the cut | disconnected cross section. The convex portion 12 is preferably a cone portion having a cone shape in which the area of the tip portion is substantially zero or a shape in which a tip portion of the cone portion is partially omitted, but is not necessarily monotonous along the direction 18. It may not be reduced, and may have an irregular shape as long as it can be approximated to a cone or a frustum. It should be noted that there may be part of a region where the cross-sectional area perpendicular to the direction 18 from the bottom 16 toward the tip 17 does not change (equal) along the direction toward the direction. Moreover, the shape where the front-end | tip was cracked (the front-end | tip is cracked and it is plural) may be sufficient. In the following description, the expression “cone portion” is defined to include both a cone shape in which the area of the tip portion is substantially 0 and a shape in which the tip of the cone portion is partially omitted. The “shape in which the tip of the cone is partially missing” described here is a virtual cone A2302 (described in FIG. 26B) formed when the cone surface 2301 shown in FIG. ) Height 2303 is 1, as shown in FIG. 26 (c), the point 2304 farthest from the apex of the virtual cone A in the missing portion is included in the bottom surface and the virtual cone It is defined as a shape in which the height 2306 of the virtual cone B2305 having the same vertex 2307 as the vertex of the body A is 1/7 or less. By having such a shape, the apparent real part of the refractive index of the structure 11 becomes smaller along the direction a.

  H / D (hereinafter sometimes referred to as aspect ratio) is preferably 1 when the length of the base of the convex portion 12 of the structure 11 is D and the height of the cone portion 12 is H. / 2 or more, more preferably 1.0 or more, still more preferably 3.0 or more, and most preferably 5.0 or more. When the convex part 12 is a cone part, H / D is 1/2 or more, and when the convex part 12 is not a cone part, H / D is 1.0 or more. When an antireflection film is formed using a body, reflection of electromagnetic waves can be effectively suppressed. In addition, H / D being 1/2 or more means that the apex angle θ of the convex portion is an acute angle in the cross-sectional projection view of the structure of this embodiment shown in FIG. . As the H / D is larger, better antireflection characteristics are often obtained. However, if the H / D is too large, the mechanical strength may decrease, so the H / D is 12 or less in view of the strength. It is preferable.

  Here, the base D indicates the shortest distance of a line segment that passes through the center of gravity of the bottom surface that is the shape of the bottom portion 16 and connects two points on the outer periphery. Moreover, the bottom part has shown the shape formed so that the terminal of a convex part may be made a round, and in other words, it is a shape enclosed by the adjacent field of convex parts.

  The height H of the convex portion 12 indicates the length of a line segment connecting the tip 17 of the convex portion 12 and the center of the bottom portion 16. When the end of the line segment connecting the tip 17 and the center of the bottom portion 16 is not in the bottom portion 16, the height H is the length of the line segment perpendicular to the plane including the bottom portion 16 from the tip 17 of the convex portion 12. Say it.

  In addition, when the tip of the convex part has a cracked shape, in the cross-sectional SEM image of the convex part, an intersection where another convex part existing adjacent to the convex part including the vertex intersects from each vertex. A plurality of virtual cones formed by extending the cone surface up to the height of the intersection closest to the substrate among the plurality of intersections in the cross-sectional SEM image of the convex portion, and the base D of the bottom portion, Assume that the height H is calculated.

  The height H of the convex portion 12 is preferably 50 nm or more, more preferably 100 nm or more, and most preferably 200 nm or more.

  The average distance between the tips 17 of the protrusions 12 (p in FIG. 1B) is preferably 400 nm or less. When the average interval between the tips of the convex portions 12 is larger than this value, light scattering becomes significant, and in the case of optical applications, the performance may be degraded.

  The shape of the convex portion 12 is preferably such that the average distance between the tips 17 is 400 nm or less, the height H (H in FIG. 1B) is 50 nm or more, and the H / D is 1.0 or more. More preferably, the average distance between 17 is 100 nm or less, the height H is 50 nm or more, and H / D is 3.0 or more, the average distance between the tips 17 is 100 nm or less, and the height H is 300 nm or more. More preferably, the H / D is 3.0 or more.

  Arbitrary arrangement | positioning can be used for arrangement | positioning of the convex part in the structure of this embodiment. For example, as shown to Fig.5 (a), forms, such as hexagonal close-packed arrangement, cubic close-packed arrangement (FIG.5 (b)), and random arrangement | positioning (FIG.5 (c)), are included. In FIG. 5, the circle schematically shows the contour of the bottom of the convex portion, the black dot at the center of the circle schematically shows the vertex of the convex portion, and the bottom surface of the convex portion does not need to be a perfect circle, and the convex portion The vertices need not be in the center of the bottom contour. In each arrangement of the convex portions schematically shown in FIG. 5, as can be seen from the schematic diagram of the cross section, the individual convex portions are formed independently.

  However, as shown in FIG. 6A, the convex portions of the structure of the present embodiment are arranged such that part of the ridge lines (or conical surfaces) of the adjacent convex portions intersect with each other above the substrate surface. May be. Moreover, the convex part does not have to contact or cross the bottom part or the ridge line, and the convex part and the convex part do not have to be in contact as shown in FIG. However, when the structure of this embodiment is used for an application such as an antireflection film to be described later, when the interval between the protrusions is increased, the ratio of the portion having a flat surface to the entire surface of the structure is increased. As a result of the increase, the refractive index change at the interface becomes steep, and there may be a problem that the antireflection characteristic is lowered. For such an application, a configuration in which the ridges of adjacent convex portions intersect with each other above the substrate surface as shown in FIG. 6A is preferable.

It is preferable that the convex part in the structure of this embodiment is uniformly formed over the entire structure. Uniformity described here refers to a state in which convex portions are distributed at a substantially constant density as shown in FIG. 7A, and there are no convex portions as shown in FIG. 7B. This refers to a state in which no region is formed. In FIG. 7, the circle schematically shows the outline of the bottom of the convex portion, and the black dot at the center of the circle schematically shows the vertex of the convex portion. As specific uniformity, when the average interval between the tips of the convex portions is p, and the standard deviation in the distribution of the intervals between the tips is σ,
0.1 <σ / p <0.5 Equation 1
It is.

  This condition means which range the degree of variation in the interval between the convex portions is relative to the value of the average interval p. When this value is smaller than 0.1, the convex portions are arranged with a constant interval, which may cause an undesirable interference effect. When this value is larger than 0.5, the convex portions are arranged. A wide distribution of the formation positions of the portions may appear as uneven optical characteristics.

  It should be noted that the tip interval calculation method obtains the coordinates of each tip by image processing of an electron micrograph taken from directly above the microstructure, and the Delaunay triangulation method (the given coordinates of each tip are apexes) And the distance between the tips of the individual protrusions is obtained by dividing the triangle so as not to include any points other than the vertices in the circumscribed circle of the triangle. In the region where the fine structure is formed, 20 electron micrographs with a field of view of 1 μm are photographed so that there is no deviation in the region, the distance between the tips is calculated, and the average interval p and the standard deviation σ are determined. Shall.

  The mesopores in the structure of the present embodiment are preferably cylindrical (cylinder shape), and preferably have a uniform diameter. More preferably, the mesopores are cylindrical and have a uniform diameter. In such a case, the process of filling the material into the hollow mesopores described later can be facilitated, and the amount of the material filled into the mesopores can be easily adjusted. Here, in the present invention and the present specification, “having a uniform diameter” means that the mesopore diameter observed by an electron microscope is within ± 50% of the average mesopore diameter. It is defined as being within.

  However, if the shape of the meso hole is not cylindrical, the effect of the present invention is not obtained. For example, the meso hole may have various shapes such as a spherical shape, an elliptical spherical shape, and a rod shape. As schematically shown in FIG. 2, when the mesopores are cylindrical, the cylindrical mesopores 21 are often oriented parallel to the substrate. FIG. 2A is a schematic view when a cylindrical meso hole is viewed from the longitudinal direction of the meso hole, and FIG. 2B is a schematic view viewed from a direction perpendicular to the longitudinal direction of the meso hole. The direction of the cylindrical mesopores need not be controlled within the structure. The above-described cylindrical mesopores having a uniform diameter are preferably periodically oriented in the structure (in other words, periodically arranged) from the viewpoint of uniform refractive index. As an example in which the mesopores are periodically arranged in the structure, as shown in FIG. 2A, regular arrangements such as hexagonal packing in which the mesopores (pores) are arranged in a hexagonal shape. The case where it arranges is mentioned. The arrangement of the mesopores is not limited to hexagonal packing, and the arrangement of the pores may be a rectangle or a square.

  In the regular arrangement, when the structure of the present invention having the mesostructure is analyzed by X-ray diffraction analysis, a diffraction peak corresponding to a periodic structure of 1.0 nm or more is preferably observed, and more preferably Preferably, a diffraction peak corresponding to a periodic structure of 5.0 nm or more is observed. Note that a diffraction peak corresponding to a periodic structure of 1.0 nm or more is observed when the structure period d defined by the regular arrangement of pores is 1.0 nm or more as shown in FIG. Is shown. Even when the shape of the mesopores is not cylindrical, the mesopores are preferably arranged regularly, and those in which a diffraction peak corresponding to a periodic structure of 5.0 nm or more is observed in the X-ray diffraction analysis are preferable. . However, if the mesopores are not regularly arranged, it does not mean that the effect of the present invention cannot be obtained. The mesopores of the structure of the present embodiment are, for example, cylindrical mesopores connected irregularly. Such a structure may be used.

  As shown in FIG. 3, the structure having a mesostructure according to the present embodiment includes a plurality of mesostructures 31 and 32 having different structures. It is possible to change the refractive index by changing the abundance of the organic compound or inorganic compound present inside the object mesopores near the bottom and the tip of the part. The different structures described here mean that there is a difference in any structural parameter such as mesopore diameter, mesopore arrangement, and mesopore spacing. In addition, in FIG. 3, although it has typically described about the case where the diameter of the meso hole near the convex part tip is larger than the diameter of the meso hole of the convex part bottom part, a plurality of meso structures having different structures in the present invention are It is not limited to the difference in mesopore diameter.

  As a substance constituting the wall portion (matrix forming mesopores) of the structure according to this embodiment, a substance containing a metal, nitride, carbide, fluoride, boride, oxide, or the like as a component can be used. . When the structure of the present invention is used for an optical material such as an antireflection film, the material constituting the wall is preferably a material with a large band gap that is transparent to visible light, and the band gap is 2.5 eV or more and 10 eV. Materials in the following ranges are preferably used. Examples include silicon oxide, titanium oxide, tin oxide, zirconia oxide, niobium oxide, tantalum oxide, aluminum oxide, tungsten oxide, hafnium oxide, zinc oxide, and the like. In particular, considering the stability of the material, silicon oxide, zirconium oxide, and titanium oxide are preferably used. Moreover, when the material which comprises a wall part is a titanium oxide, it is preferable that at least one part of a titanium oxide is crystallizing. This is because at least part of the titanium oxide is crystallized, so that the refractive index of the wall material can be further increased as compared with the case where it is not crystallized. This is because the properties of the above are remarkably exhibited. Note that crystallization of titanium oxide can be measured by X-ray diffraction analysis or the like.

  The mesopores 13 in the structure according to the present embodiment may have voids (hollow) inside the mesopores, or organic materials or inorganic materials may exist inside the mesopores. Here, the presence of an organic material or an inorganic material inside a mesopore means that when only an organic material is present inside a mesopore, or when only an inorganic material is present, an organic material and an inorganic material such as an organic-inorganic hybrid material are present. Of course, when present, organic or inorganic and other materials may be present. In addition, when an organic material or an inorganic material is present inside the mesopores, it is sufficient that the organic material or the inorganic material is present in at least a part of the mesopores. The case where it is present in a completely filled state and the case where most of the mesopores among the plurality of mesopores are mesopores in which an organic material or an inorganic material exists in a part of the inside are included. In the present invention, even when all of the plurality of mesopores are completely filled with an organic material or an inorganic material, the mesostructure has mesopores, and an organic material or an inorganic material exists inside the mesopore. Therefore, it is included in the concept that “the mesostructure has mesopores”.

  Examples of the organic material present in the mesopore include, for example, an amphiphile used as a structure-directing agent in the production of a mesostructure described later, a polymer material such as a polymer, and a monomolecular having a molecular weight of less than 10,000. Examples include meric materials.

  Further, as an example in which an organic material is present inside the mesopores, there is an example in which the organic material has a hydrophobic functional group and the surface of the mesopore is chemically modified with a hydrophobic functional group. In such a case, as will be described later, it is possible to control the form of the structure having a plurality of convex portions to be formed. Here, in the present invention and the present specification, the hydrophobic functional group means that when the surface of a clean fused quartz substrate is modified with the compound to a saturation level, the contact angle of water on the modified surface is more than 90 °. Is also defined as a large functional group. Examples of such hydrophobic functional groups include alkyl groups and fluoroalkyl groups.

  The inorganic material present inside the mesopores can be selected from a wide range of materials such as conductive materials, insulating materials, and semiconductor materials.

  Examples of inorganic materials that can be used include metals, nitrides, carbides, fluorides, borides, oxides, and the like as main components. The inorganic material may be a single composition or a mixture of two or more kinds or a composite material. When the structure of this embodiment is used for an optical material such as an antireflection film, the inorganic material present in the mesopores is preferably a material having a large band gap and being transparent to visible light. A material having a band gap in the range of 0.5 eV or more and 10 eV or less is particularly preferably used. Examples include silicon oxide, titanium oxide, tin oxide, zirconia oxide, niobium oxide, tantalum oxide, aluminum oxide, tungsten oxide, hafnium oxide, zinc oxide, etc., especially silicon oxide, zirconium oxide, titanium oxide. High transparency is preferable from the viewpoint of optical application.

  The inorganic material present in the mesopores is contained so as to be uniformly distributed in the mesopores of the structure having the convex portions as schematically shown in FIGS. 4 (a) and (b). Preferably, the porosity is increased in the direction from the bottom to the tip of the projection so that the filling rate of the inorganic material into the mesopores decreases in the direction from the bottom to the tip of the projection. In this way, the filling amount may be controlled. Such a local change in the filling rate can be achieved, for example, by configuring the mesostructure forming the convex portion with a plurality of mesostructures having different structures as described above ( FIG. 4 (d)).

  In the case of a structure in which the filling rate of the inorganic material into the mesopores decreases in the direction from the bottom to the tip of the convex portion, a material that forms the structure having the mesostructure of the element constituting the inorganic material The value of (amount of elements constituting the inorganic material) / (amount of elements constituting the structure having a mesostructure) representing the local abundance ratio with respect to the constituent elements decreases in the direction from the bottom to the tip of the convex part. (FIG. 4C).

The value of (amount of elements constituting the inorganic material) / (amount of elements constituting the structure having a mesostructure) described above can be obtained by depth direction analysis of photoelectron spectroscopy performed while repeating ion sputtering.
In addition, when filling all mesopores, it is preferable that the material which comprises a wall part and the material which exists in a mesopore differ.

The structure of this embodiment is often formed on a substrate. The material and shape of the substrate are basically not limited as long as the structure of the present invention can be formed thereon.
Moreover, the structure of this embodiment may have a protective layer on the surface.
Hereinafter, the protective layer will be described in detail.

  FIG. 24 shows a schematic diagram of a structure composed of convex portions on the surface. The convex portion 2202 formed on the base body 2201 has the protective layer 2203 on the surface, whereby the mesopores 2204 included in the convex portion 2202 are shielded from the atmosphere containing moisture. As a result, moisture adsorption into the mesostructure forming the convex portion 2202 can be inhibited, and a stable refractive index can be maintained. Similarly, a substrate containing an oxide component such as an alkali metal oxide, an alkaline earth metal oxide, or boron oxide by inhibiting moisture from reaching the substrate 2201 through the mesopores 2204 was used. Even in this case, it is possible to prevent the occurrence of fogging and whitening due to elution of these components. In addition, the void | hole described here also includes the void | hole produced in the part which is not completely filled when an organic material or an inorganic material is filled into at least one part in a void | hole. Similarly, in the following description, the porosity means the porosity with respect to the total volume of the organic material or inorganic material when organic material or inorganic material is present in at least a part of the pore. Refers to the percentage of

  As a material for forming the protective layer, it is desirable to select a material having a porosity smaller than that of the convex portion for the purpose of suppressing the intrusion of moisture into the convex portion having pores. The magnitude of the porosity can be evaluated by, for example, an adsorption / desorption isotherm obtained by a nitrogen gas adsorption method with or without a protective layer. The adsorption / desorption isotherm described here refers to an isotherm defined by IUPAC, and is described in the document “Pure Appl. Chem., 57, p. 603 (1985)”. Specifically, if there is only a convex part without a protective layer, or if a protective layer with a higher porosity than the convex part is formed on the surface, adsorption / desorption with respect to the pores inside the convex part is dominant. As an isotherm, it exhibits IV type adsorption / desorption behavior. On the other hand, when a protective layer having a lower porosity than the convex portion is formed on the surface, the adsorption / desorption behavior regarding the pores inside the convex portion is hindered by the protective layer, resulting in adsorption / desorption on the protective layer surface. Since the desorption behavior is dominant, the adsorption / desorption behavior is behavior of type II or close to type II.

  The protective layer desirably covers the entire region of the surface of the convex portion having mesopores, but there may be a region where the protective layer is not partially formed for convenience of manufacture. Even in such a case, the effect of the protective layer can be expected, but it is desirable that the protective layer is formed on at least 50% or more of the surface of the convex part having mesopores.

  Hereinafter, the convex part which has a mesostructure, and the protective layer formed in the surface are demonstrated in detail using FIG. Here, the meso hole 2204 existing inside the convex portion is schematically shown as a round shape, but the shape of the meso hole is not particularly limited, and the meso holes may be connected to each other.

  FIG. 25A is a schematic diagram illustrating an example of a structure having a protective layer. In the convex portion 2202 including the mesopores 2204, the protective layer 2203 is formed only on the surface portion, and the porosity inside the convex portion maintains the state before the protective layer is formed. As a means for producing such a structure, for example, a plasma assisted atomic layer deposition method as described in “Journal of American Chemical Society 128, p. 11018 (2006)” can be used.

  FIG. 25B is a schematic diagram illustrating another example of a structure having a protective layer. When mesopores are exposed to the outside on the surface of the convex portion 2202 having mesopores, and when these mesopores are continuous from the surface of the convex portion to a certain depth, the protective layer 2203 is formed. In some cases, the material to be filled penetrates from the surface to the mesopores corresponding to several layers. Even in this case, the formed protective layer 2203 functions to block moisture in the atmosphere. Therefore, a structure including a convex portion may have such a structure as long as the refractive index continuously decreases in the direction from the bottom surface of the convex portion toward the tip.

  FIG. 25C is a schematic view showing still another example of a structure having a protective layer. In this example, an organic material or an inorganic material is present in the mesopores 2206 of the convex portion 2202, and the protective layer 2203 is formed on the surface of the convex portion. At this time, the material for forming the protective layer 2203 is not particularly limited as long as it has a porosity of a value lower than the porosity of the convex portions before the protective layer is formed. Further, the material (organic material or inorganic material) present in the mesopores and the material forming the protective layer may be the same material. Such a structure can be easily obtained by, for example, forming a convex part having mesopores, filling an organic or inorganic material in the mesopores, and forming a protective layer on the surface of the mesopores. . In addition to a film forming method using a general vacuum apparatus, film forming by coating such as a spin coating method or a dip coating method can also be used. Moreover, you may form a protective layer on the surface of a convex part with the same material and the same process as the material (organic material or inorganic material) with which a mesopore is filled. In such a case, it is possible to form a protective layer by filling the mesopores with an organic material or an inorganic material and continuing the filling as it is, and filling the mesopores with an organic material or an inorganic material. Then, it is possible to form the protective layer by stopping the filling and then restarting the filling.

  Specific examples of the material for forming the protective layer include silicon oxide, titanium oxide, zirconium oxide, and aluminum phosphate.

  The thickness of the protective layer is preferably 1 nm or more and 20 nm or less. When the thickness of the protective layer is less than 1 nm, sufficient film thickness uniformity cannot be maintained, and the effect of shielding moisture in the atmosphere may not be sufficiently obtained. Further, when the thickness of the protective layer is larger than 20 nm, the ratio of the protective layer to the convex shape of the present invention becomes too large. For example, when the structure is used as an antireflection film, In some cases, the continuous change in the refractive index in the portion is partially offset.

<Second Embodiment>
The structure of the present embodiment is a structure having a plurality of protrusions on the surface, and the cross section when the protrusion is cut along a plane perpendicular to the direction from the bottom to the tip of the protrusion is the direction. The convex portion has a mesostructure having mesopores, a metal element is present at the tip of the convex portion, and the length of the bottom side of the convex portion is D, H / D is 2.0 or more, where H is the height of the convex portion.

The structure of this embodiment is different in that the shape of the convex portion is different, the metal element is present at the tip of the convex portion, the height of the convex portion is H, and the length of the base of the convex portion is H. Except that / D is 2.0 or more, it is the same as the first embodiment.
Therefore, only different points will be described below.

  The metal element present at the tip of the convex portion of the structure of the present embodiment may include a member constituting an etching chamber of the plasma etching apparatus. As will be described later in the description of the manufacturing method, the structure of the present embodiment adjusts the conditions of the plasma etching process, and during the etching process, the substance including the member constituting the etching chamber has fine domains on the film surface. The substance formed in the domain shape can be manufactured as an etching resistant material. In this case, a structure in which a substance including a member constituting an etching chamber of the plasma etching apparatus remains is formed at the tip of the convex portion. The substance containing the member constituting the etching chamber of the plasma etching apparatus is typically a substance containing a metal element, and particularly a substance containing aluminum.

  As will be described later in the description of the manufacturing method of the structure according to the present embodiment, when the metal element is present at the tip of the protrusion as described above, the aspect ratio of the protrusion of the structure has a high aspect ratio (H / D is likely to be 2.0 or more).

<Third embodiment>
The structure of the present embodiment has a plurality of protrusions, and the cross-sectional area when the protrusions are cut along a plane perpendicular to the direction from the bottom to the tip of the protrusions is reduced along the direction. When the average distance between the tips of adjacent convex portions is 100 nm or less, the length of the base of the convex portion is D, and the height of the convex portion is H, H / D is It is a structure characterized by being 1/2 or more.

  The shape of the structure having a plurality of protrusions is basically the same as the shape of the structure described in the first embodiment shown in FIG. 1 and has a shape having a plurality of protrusions. The structure of this embodiment does not have mesopores. The average interval between the tips of adjacent convex portions of the structure of the present embodiment is 100 nm or less, and the length of the base of the convex portion is D, and the height of the convex portion is H. The aspect ratio defined by this value is ½ or more. By forming such a structure on the substrate, the reflectance on the substrate surface can be significantly reduced. The reflectance reduction effect is confirmed with an aspect ratio of ½ or more, but the aspect ratio is preferably higher, more preferably 1 or more, and further preferably √3 / 2 or more. A structure having such morphological features is difficult to manufacture by a conventional material processing technique, and can be manufactured by the manufacturing method of this embodiment described later.

Further, similarly to the first embodiment, it is preferable that the convex portions in the structure of the present embodiment exist uniformly over the entire structure. Specifically, when the average interval between the tips of the convex portions is p, and the standard deviation in the distribution of the intervals between the tips is σ,
0.1 <σ / p <0.5 Equation 1
It is preferable that

<Fourth embodiment>
The antireflection film of this embodiment has the structure described in any one of the first to third embodiments.

  In the structures described in the first to third embodiments described above, the area of the cross section when the convex part is cut in a direction perpendicular to the direction from the bottom part of the convex part to the tip is in the direction. By having a plurality of convex portions having a shape that decreases along the surface, the apparent refractive index real portion decreases along the direction from the bottom to the tip of the convex portion, so the refractive index between the air and the structure Change will be gradual. Accordingly, when the structures described in the first to third embodiments are all formed on the surface of the substrate, the steepness of the refractive index change at the optical interface is reduced, and as a result, visible light to near-infrared light is emitted. It suppresses reflection and functions as an excellent antireflection film.

  The wavelength range of the electromagnetic wave in which the antireflection film of this embodiment exhibits antireflection ability is in the visible light to near infrared region.

Furthermore, the antireflection film of this embodiment is formed using a material having a refractive index substantially equal to that of the substrate, or the refractive index of the structure is within the mesopores of the structure of the present invention made of the mesostructure. By controlling the porosity of mesopores to match the refractive index of the substrate or introducing other materials with controlled materials and amounts, the difference in refractive index at the interface between the substrate and the antireflection film of this embodiment The reflection by can be suppressed.
This will be described with reference to FIG.

The effective refractive index nfilm of the microstructure described in the first to third embodiments is expressed by the following formula (3), and each value is appropriately set according to the member to be subjected to antireflection. Can do.

Normally, when the second material is formed on the base made of the first material, the electromagnetic wave having a wavelength that passes through the second material, as shown in FIG. Reflection R2 and reflection R1 on the second material surface occur. Here, by forming the antireflection film of the present embodiment on the surface of the second material, the reflection Rtotal is reduced by the reflection R1 that is reduced by the shape effect of the microstructure (convex portion) of the antireflection film. , Determined by the reflection R2 of the interface between the member and the microstructure, and expressed by the formula (4),

  Since the interface cannot be defined on the surface of the second material, the reflectance is greatly reduced.

  However, even in such a case, if the refractive index of the first material is different from that of the second material, reflection R2 at the interface between the base and the second material cannot be prevented (FIG. 8B). ).

  FIG. 22 shows the relationship between the refractive index nsub of the member for preventing reflection and the effective refractive index n3 (n_film) of the microstructure and the reflectance at the interface between the two. In FIG. 22, n_sub is indicated by n4, and the effective refractive index n_film of the fine structure is indicated by n3.

Here, if the refractive indexes of the first and second materials are matched, as shown in FIG. 8C, both R1 and R2 can be suppressed, and reflection does not occur in principle. In other words, in addition to reducing the reflection (R1) due to the shape effect of the fine structure 203, the reflection (R2) can be reduced by aligning the refractive index of the fine structure and the member. It can be realized.
As the range of the refractive index difference (n_sub−n_film) of both, it is more preferable that the relationship between the two satisfies the following formula (5).

  In the antireflection film of this embodiment, this suppression of R1 and R2 is achieved at the same time, but as a method of suppressing R2, a material having a refractive index matching that of the first material is used in the present embodiment. A method of forming the fine structure (convex portion) of the antireflection film, and after forming the fine structure (convex portion) in the mesostructure, the amount of material having an appropriate refractive index is controlled in the mesopores. In other words, there is a method for matching the refractive indexes of the structure and the substrate by introducing them. FIG. 8D is a graph showing changes in the refractive index when titanium oxide is introduced into the pores of a silica mesostructure having hollow mesopores. As can be seen from the figure, the refractive index can be precisely controlled by the porosity of the original silica mesostructure and the amount of titanium oxide introduced. Here, an example related to the introduction of titanium oxide was shown, but by changing the material to be introduced into the pores, it is possible to change the rate of change in refractive index with the amount of mesostructured material having the same porosity. It is.

  Thus, the formed conical surfaces of the adjacent convex portions are bonded to each other, the portion where the conical surfaces are bonded to each other is on the antireflection film side of the surface of the base, and the conical surfaces are It is preferable that the distance between the portion to be bonded and the substrate is not constant. This is because the rate of change in the refractive index at the interface between the base and the antireflection film is reduced and the antireflection effect is further increased because the distance between the portion where the conical surfaces are bonded to the base is not constant.

When the structure of the antireflection film of this embodiment has a mesostructure, the layer of the antireflection film that contacts the base has a mesostructure, and the refractive index of the base is na, Of the layers constituting the antireflection film, when the refractive index of the layer in contact with the substrate is nb,
0 ≦ | na−nb | ≦ 0.05
It is preferable that

  This can be achieved by controlling the porosity so that the refractive index of the structure in contact with the substrate matches the refractive index of the substrate or by introducing other materials into the mesopores with controlled material and quantity. In the optical member having the antireflection film and the substrate of the embodiment, the refractive index difference between the interface between the substrate and the antireflection film is 0.05 or less, and the air and the structure at the tip of the convex portion of the structure This is because a high antireflection effect can be realized by a moderate change in refractive index.

  The substrate of the optical element having the antireflection film of this embodiment present on the surface of the substrate is preferably a substrate that collects visible light (that is, a convex lens) or a substrate that emits visible light (that is, a concave lens). In such a case, the antireflection effect is particularly high.

  Further, in the optical member having the base and the antireflection film of this embodiment, the structure of the antireflection film has a mesostructure, and an organic material or an inorganic material is present inside the mesopores of the structure. The mesopores of the mesostructure are preferably periodically oriented in the normal direction of the substrate. In other words, the structure of the antireflection film can also be expressed as having a single crystallographic orientation with respect to the mesostructured substrate. With such a structure, the filling amount can be easily controlled when filling the inside of the mesopores with an organic material or an inorganic material.

<Fifth embodiment>
The water repellent film of the present embodiment is a water repellent film having a structure in which an organic material is present inside the mesopores of the structure described in the first embodiment.

That is, the water-repellent film of the present embodiment has a structure having a plurality of protrusions on the surface, the protrusions have a mesostructure, and the mesostructure has a mesopore. The water-repellent film is characterized in that an organic material is present in the inside.
The structure of the water-repellent film of this embodiment is schematically shown in FIG.

In the water-repellent film of the present embodiment, an organic material exists in the mesopores of the structure, but the organic material present in the mesopores preferably has a hydrophobic functional group. Here, the organic material present inside the mesopores may be present in all the mesopores, or may be present only in some mesopores. Moreover, it may exist only on the surface of all the mesopores, or may exist only on the surface of some mesopores. When an organic material having a hydrophobic functional group exists only on the surface of the mesopores, it can also be expressed that the surface of the mesopores is modified with a hydrophobic functional group. Furthermore, an organic material in which the surface of the mesopore is modified with a hydrophobic functional group and the hydrophobic functional group is present inside the mesopore may be present.
This will be described in detail with reference to the schematic diagram of FIG.

  The presence of the organic material in the mesopores means that the organic material 13 containing an organic compound as a component exists in the mesopores as shown in FIG. 4A, and as shown in FIG. This includes any case where the surface of the mesoporous material is modified with an organic material such as a hydrophobic functional group 14. The modification with the hydrophobic functional group may include not only the surface of the mesopore but also the mesopore filled with the hydrophobic functional group. Further, the introduction amount and the modification amount are not necessarily uniform as shown in FIG. In FIG. 4 (b), the inner wall of the mesopore is depicted as completely covered with a hydrophobic functional group, but the coverage is incomplete and the mesopore pore wall is partially exposed. You may do it. Even if it is not completely covered with a hydrophobic functional group, when the hydrophobic functional group contains an alkyl group or a fluoroalkyl group, the water repellent effect is remarkable.

Below, the example of the functional group formed in the mesopore surface is shown. However, functional groups that can be used in the present invention are not limited to these. Each modifying group preferably forms a covalent bond with the main skeleton of the mesoporous film via an oxygen atom. N in the examples of the functional groups listed below indicates the number of hydrophobic groups directly bonded to the silicon atom in the modifying group. The material into which these modifying groups are introduced is preferably a silane coupling agent, and alkoxides or halides having these functional groups are preferably used. There is no limitation on the method of introducing the hydrophobic modifying group into the mesoporous film, and chemical vapor deposition, immersion in a solution containing the raw material of the hydrophobic modifying group, or the like is used.

  The water-repellent film of the present embodiment has excellent water-repellent performance due to its fine characteristic surface shape and the hydrophobic property of the organic material existing inside the mesopores. The water-repellent film of this embodiment is excellent in durability because the organic material present inside is exposed to the surface even when the surface layer is partially destroyed by mechanical impact or wear. Has features.

  Further, in the water-repellent film of the present embodiment, the plurality of convex portions are present on a surface having a concave and convex shape, and the cycle and height of the concave and convex shapes are larger than the cycle and height of the plurality of convex portions. preferable. In such a case, the water-repellent film is composed of a plurality of layers, the layer b having the above-described structure exists on the surface of the layer a having a plurality of protrusions, and one protrusion of the layer a has one protrusion. It is good also as a structure where the some convex part which the layer b has on the surface exists.

  In such a case, a remarkable water-repellent effect may be exhibited by increasing the apparent surface area. As described above, the plurality of convex portions of the water-repellent film of the present embodiment can be formed without installing a mask. As a result, it is possible to uniformly form fine convex portions even on a non-flat surface, which is difficult to form convex portions by the conventional method using a mask. It is known that a water-repellent film having a convex portion on the surface exhibits a higher water-repellent effect as the surface area modified with a hydrophobic functional group increases. Therefore, after forming the first concavo-convex shape having a larger period and height difference than the above-described convex portion on the surface in advance, forming a fine convex portion on the surface of the first concavo-convex shape, Increase the apparent surface area. Further, by modifying the surface of the convex portion and the surface of the mesopores with a hydrophobic functional group, a water-repellent film having a more excellent surface water repellency can be obtained. This will be described with reference to FIG.

    In FIG. 19A, a conical first concavo-convex shape (average interval between tips: p ′, height of tip portion: H ′) is formed on a substrate 1902, and the surface thereof has a mesostructure. And a structure 1901 having a plurality of fine convex portions in which an organic material exists in at least a part of mesopores in the mesostructure (average distance between tips: p, height of tips: H) It is a schematic diagram which shows an example of the water repellent film of embodiment. At this time, by designing p ′ larger than p and H ′ larger than H, the shape of the surface becomes similar to a fractal structure. As a result, the apparent surface area increases, and as a result, the water repellency of the surface can be further increased. In FIG. 19A, H ′ is defined to indicate the maximum height difference in the height of the tip in the region corresponding to a certain period in the first concavo-convex shape. As the shape of the first unevenness, a rectangular shape can also be preferably used. In this case, a film having a structure as schematically shown in FIG. 19B is obtained by forming the structure described in the first embodiment having an organic material inside the mesopores. Also in this case, like FIG. 19A described above, by designing p ′ larger than p and H ′ larger than H, the apparent surface area increases, and as a result, the surface repelling is increased. The aqueous property can be further increased.

  There is no particular limitation on the upper limit value of p ′ when forming such a first concavo-convex shape, but in consideration of the size of water droplets that are actually generated on the surface of the water-repellent film, the effect of improving water repellency Is preferably about 1 mm or less. Further, there is no particular limitation on the upper limit value of H ′ when forming the first concavo-convex shape, but in consideration of the difficulty level of the manufacturing process of the first concavo-convex shape, H ′ is about 10 μm or less. It is desirable.

  In the structure of the water repellent film of this embodiment, the substance constituting the wall of the mesostructure is preferably silicon oxide from the viewpoint of stability, ease of surface modification, and the like.

  In addition, the water repellent film of the present embodiment described above is defined as having a contact angle with respect to water droplets of 150 degrees or more on the surface. This large contact angle is a value that cannot be achieved with a flat surface substrate having no irregularities, no matter how large the surface hydrophobicity is.

<Sixth embodiment>
The substrate for mass spectrometry of the present embodiment includes a base having conductivity, and the structure according to the first or second embodiment in which the wall portion of the mesostructure existing on the surface of the base is titanium oxide. A substrate for mass spectrometry.

  Another embodiment of the mass spectrometric substrate included in the present embodiment includes a conductive substrate, and the structure according to the third embodiment in which convex portions present on the surface of the substrate are made of titanium oxide. And a substrate for mass spectrometry.

  This restriction on the material is due to two requirements that titanium oxide has conductivity and that it has strong absorption in the wavelength region of the laser beam for mass spectrometry excitation. The titanium oxide forming the pore walls may be amorphous or partly crystallized, but the ionization efficiency is further increased and the S / N ratio is increased in the case of containing microcrystals. It is preferable for improvement.

  For this reason, as a result of the steepness of the optical interface being lowered, reflection of the probe light on the surface of the structure can be prevented. That is, the substrate for mass spectrometry of this embodiment can improve the efficiency of ionization by preventing reflection while retaining a fine structure that has a role of preventing destruction of the specimen sample accompanying ionization. is there. There is another advantage when the substrate for mass spectrometry of this embodiment has a mesostructure and the inside of the mesopores of the mesostructure is a void. This is because the formation of the fine structure increases the specific surface area of the membrane, that is, the number of mesopore openings increases, so that the analyte molecules ionized by laser irradiation desorb from the mesopores on which they were retained. The effect is that it is easy to release. The pore diameter of the mesoporous titanium oxide film when the substrate for mass spectrometry of the present embodiment has mesopores with voids inside is preferably optimized according to the size of the substance to be detected. A typical pore diameter is 5 nanometers or more, and in the case of detecting a bio-related molecule having a large molecular size, a pore diameter of 10 nanometers or more is often used preferably. The pore diameter can be controlled by the type of surfactant used and the solution composition as described above.

<Seventh embodiment>
The phase plate of the present embodiment has a mesopore in the structure described in the first embodiment or the second embodiment, and the orientation direction of the mesopore is perpendicular to the thickness direction of the structure. It is composed of a structure that is controlled in one direction on a flat surface. In this structure, since the apparent density differs between the direction parallel to the mesopores and the direction perpendicular to the mesopores, it is possible to obtain a mesostructured thin film having a different refractive index in the two directions, that is, having birefringence. . In this case, the difference in refractive index between the two directions is larger as the refractive index of the material forming the pore wall is higher, and is larger when the inside of the pore is a cavity. Since these oriented hollow mesostructured thin films have birefringence, they function as phase plates having desired characteristics by changing the film thickness in accordance with the birefringence value.

  For example, if the birefringence value Δn is 0.1, the retardation can be set to 100 nm by setting the film thickness to 1 μm, and the film can be used as a quarter wavelength plate for light having a wavelength of 400 nm. Functions and can convert linearly polarized light into circularly polarized light.

  By making the surface of the mesostructured thin film having such birefringence into a structure having the shape described in the first embodiment or the second embodiment, the reflection on the film surface is suppressed. A phase plate having excellent characteristics can be obtained.

  Next, the example of the manufacturing method of the structure as described in 1st-3rd embodiment is demonstrated in detail.

  In the structure according to the third embodiment, for example, a reactive gas is used to plasma-etch an inorganic oxide without using a mask, and the average distance between the tips of the inorganic oxide is 400 nm or less and It can be formed by a method of manufacturing a structure having a step of forming a plurality of convex portions having a shape in which a cross-sectional area when cut by a plane perpendicular to the direction from the bottom to the tip is reduced along the direction. . In the case of the manufacturing method of the structure having such a process, the cross section of the inorganic oxide is cut by plasma etching on a plane perpendicular to the direction from the bottom to the tip, and the average distance between the tips is 400 nm or less. A plurality of convex portions having a shape whose area decreases along the direction can be formed, and the structure described in the third embodiment can also be obtained.

Gas species used for plasma etching are ionized by plasma and chemically reacted with the inorganic oxide to form a volatile compound, thereby causing etching to proceed. As a plasma generation method for plasma etching, known methods such as capacitive coupling, inductive coupling (ICP), electron cyclotron resonance (ECR), and magnetic neutral line discharge (NLD) can be used. An ICP method that can obtain a high-density (10 ¹² atoms · cm ⁻³ ) plasma at a gas pressure of 10 Pa or less with a relatively simple apparatus configuration is preferably used. The gas used for plasma etching of the inorganic oxide is preferably one containing fluorine. For example, a sulfide such as SF ₆ or a fluorocabon-based gas represented by CxFy is used.

  A plurality of convex portions can be formed on the surface of the inorganic oxide by appropriately controlling the plasma etching conditions. The convex portion described here has a shape in which the area of a cross section cut by a plane 19 perpendicular to the direction 18 from the bottom portion 16 toward the tip end 17 becomes smaller along the direction 18, and as described above, the convex portion is a cone. If the height of the virtual cone formed when the cone surface of the cone is extended is 1, the virtual cone Of the portion missing from the tip of the body is a shape in which the distance from the virtual tip to the farthest point is 1/7 or less.

The etching conditions described here refer to gas pressure, power of a high-frequency electric field applied for plasma formation, power of a high-frequency electric field applied to a cathode where an object to be etched is placed, etching time, substrate temperature, and the like. . Typically, the pressure of the gas is about 0.05 Pa to 20 Pa, the power of the high frequency electric field applied for plasma formation is 100 to 500 W, and the power density of the high frequency electric field applied to the cathode on which the etching target is placed is 0.1. ˜2.5 W · cm ⁻³ , etching time is 10 seconds to 5 hours, and substrate temperature is room temperature to 200 ° C.

For example, in the plasma etching step, the structure described in the third embodiment is etched while at least a part (part or all) of the reactive gas component is contained in the inorganic oxide. As a result, the inorganic oxide and the components contained in the reactive gas are combined, and a microstructure having a plurality of protrusions is formed on the inorganic oxide due to the difference in etching resistance between the combined portion and other portions. can do. For example, when the inorganic oxide is SiO ₂ , SiOxFy is locally formed, and due to the difference in etching resistance between this portion and SiO ₂ that has not reacted with the etching gas, a plurality of convex portions are formed on SiO _2. A fine structure is formed.

The reactive gas preferably contains fluorine. For example, a sulfide such as SF ₆ or a fluorocaobon-based gas represented by CxFy is used.

  The etching conditions need to be optimized in accordance with the material of the inorganic oxide material forming the convex portions. However, when various conditions are optimized and the etching rate is 10 nm / min or less, The structure described in the third embodiment is preferably formed.

  The inorganic oxide subjected to plasma etching is preferably a substance having a band gap in the range of 2.5 eV or more and 10 eV or less, and most preferably silicon oxide, zirconium oxide or titanium oxide.

Next, an example of a method for manufacturing the structure described in the first embodiment will be described.
The structure described in the first embodiment includes, for example, a step of forming a mesostructure having mesopores, plasma etching is performed on the mesostructure, and the mesostructure is a convex portion from the bottom to the tip Forming a plurality of convex portions having a shape in which the area of the cross section when the convex portions are cut in a plane perpendicular to the direction toward the direction becomes smaller along the direction. It can be manufactured by a manufacturing method or the like.

  Referring to FIG. 1 (c), a plurality of convex portions 12 are formed on the mesostructure surface by a step of forming a mesostructure 15 having mesopores 13 and a step of plasma etching the formed mesostructure. By forming, the structure 11 described in the first embodiment is manufactured.

  Here, the process of forming the mesostructure will be described in detail. As described above, the mesostructure is a structure in which mesopores are voids (hollow), or mesopores in which an organic material or an inorganic material exists are arranged in a matrix of a material that forms pore walls. Point to.

  Therefore, the step of forming a mesostructure having mesopores described herein may be a step of forming a mesostructure having mesopores having voids inside, and an organic material or an inorganic material exists inside. It may be a step of forming a mesostructure having mesopores. When the step of forming the mesostructure having mesopores is a step of forming mesopores having an organic material or an inorganic material inside, the organic material or inorganic material is inside the mesopores at the stage of formation. A step of forming a mesostructure having mesopores having voids inside, and a step of filling an organic material or an inorganic material into mesopores having voids inside. Also good.

  Further, the step of forming the mesostructure having mesopores is a step of forming a mesostructure having mesopores whose inside is a void, and a plurality of protrusions are formed after the step of forming the plurality of protrusions on the mesostructure. There may be a step of filling the mesopores of the mesostructured body having a convex portion with an organic material or an inorganic material.

  In the present invention and the present specification, when “B or C is present in A” is described, it is understood that both B and C are present in A. Needless to say, A includes a complex of B and C.

  The step of forming a mesostructure having mesopores is not particularly limited. For example, from a precursor solution containing an amphiphile and an inorganic oxide precursor, a sol-gel method or the like is used. Can be produced by a method. In this case, a mesostructure in which the molecular assembly of the amphiphile is arranged in a matrix of an inorganic material is spontaneously formed. That is, the molecular assembly functions as a template for forming mesopores. By removing the amphiphilic substance in the template by a process such as baking, extraction with a solvent, oxidation with ozone, ultraviolet irradiation, etc., a hollow structure (structure in which mesopores are voids) can be formed. It is also possible to introduce a material different from the amphiphile into the mesopores. As a method for introducing an organic material or an inorganic material into the mesopores, a particularly preferable method is a chemical vapor deposition method, a layer-by-layer deposition method, or a sol-gel method.

  As described in the first embodiment, the material used for forming the mesostructure is preferably transparent in the visible range. For this reason, the material forming the mesostructure has a band gap of 2.5 eV. The substance is preferably in the range of 10 eV or less. Needless to say, substances having a band gap in the range of 2.5 eV to 10 eV include substances having a band gap in the range of 5.0 eV to 10 eV. Particularly preferred is any one of silicon oxide, zirconium oxide and titanium oxide.

  The amphiphilic substance used for producing the mesostructure is not particularly limited, but is preferably a surfactant. Examples of the surfactant molecule include ionic and nonionic surfactants. Examples of the ionic surfactant include a halide salt of trimethylalkylammonium ion. The chain length of the alkyl chain of the halide salt of trimethylalkylammonium ion is preferably 10 to 22 carbon atoms. As the nonionic surfactant, one containing polyethylene glycol as a hydrophilic group can be used. As the surfactant containing polyethylene glycol as a hydrophilic group, polyethylene glycol alkyl ether and polyethylene glycol-polypropylene glycol-polyethylene glycol block copolymers can be used. It is possible to change the structural period by changing the size of the hydrophobic component and the hydrophilic component. In general, it is possible to enlarge the pore diameter by increasing the hydrophobic component and the hydrophilic component. In addition, the preferable alkyl chain length of polyethylene glycol alkyl ether is C10-22, and the preferable repeating number of PEG is C2-50. In addition to the surfactant, an additive for adjusting the structural period may be added. As an additive for adjusting the structure period, a hydrophobic substance can be used. As this hydrophobic substance, alkanes and aromatic compounds not containing a hydrophilic group can be used, and specifically, octane or the like can be used.

  As the precursor of the inorganic oxide, silicon or metal element alkoxide or halide can be used. As the alkoxide, methoxide, ethoxide, propoxide, or one in which a part thereof is substituted with an alkyl group can be used. As the halogen, chlorine is most commonly used.

  The mesostructure possessed by the structure described in the first embodiment can be produced, for example, by applying or casting the precursor solution described above. As the coating process, dip coating, spin coating, mist coating, etc. are common. It is also possible to produce the mesostructure of the present invention by a hydrothermal synthesis method different from the coating process. In this case, the substrate is held in the precursor solution, and the mesostructure is generated by heterogeneous nucleation-nucleus growth. A structure is formed. It is also possible to form a film by a chemical vapor deposition method.

  Furthermore, the mesostructure of the structure described in the first embodiment may be a plurality of mesostructures having different structures. In such a case, in the step of forming a mesostructure having mesopores, by using a process such as applying a plurality of layers of a precursor solution in which the surfactant species to be used and the surfactant concentration are changed, Structures having mesostructures with different structures can be formed.

  The step of performing plasma etching on the mesostructure and forming a plurality of convex portions on the mesostructure is preferably performed without using a mask. The mask described here refers to a mesostructured film and a plasma, which are targets for forming protrusions in the etching process in order to form a region that is not partially etched in the process of etching the mesostructured body. It is installed between the two and serves to partially prevent the mesostructure from being exposed to plasma. Resist patterns formed by methods such as photolithography and nanoimprint on the mesostructure, shield plates with holes, etc. including.

  Therefore, the mask described here is intentionally formed or installed, and is like contamination that is spontaneously formed on the mesostructure in the plasma etching process as described later. Are not included in the definition of a mask.

The above-described plasma etching is preferably an etching method in which a reactive gas that reacts with the material forming the mesostructure is used, and the mesostructure is etched while containing a component of the reactive gas. As in the case of manufacturing the structure described above, formed by etching an inorganic oxide material, this allows at least a part of the reactive gas to be contained in the inorganic oxide and the inorganic oxide and the A fine structure having a plurality of convex portions can be formed by forming a bond portion with a component contained in the reactive gas and utilizing a difference in etching resistance between the bond portion and the other portion. The reactive gas is preferably a gas containing fluorine. For example, when the material has mesopores is SiO ₂ is, SiOxFy is locally formed, and this portion, the difference in etching resistance between the SiO ₂ which has not reacted with the etching gas, a SiO ₂ A plurality of convex portions having a fine structure are formed. This is confirmed, for example, by composition analysis of the surface of the mesostructure body with the time of the plasma etching process in the present invention.

  FIG. 9 shows fluorine detected on the film surface with the plasma etching time when the silica mesostructure is etched using an etching gas containing fluorine as a component to produce a structure having a convex portion of the present invention. It is a graph showing the result of having analyzed the change of the quantity of x-ray photoelectron spectroscopy. From this figure, with the etching time, that is, the film thickness (corresponding to t in FIG. 9B) of the porous film having a plurality of convex portions having a fine structure decreases, and the amount of fluorine gradually increases. It is confirmed that X-ray photoelectron spectroscopy analysis in the depth direction confirms that fluorine atoms are present not only on the film surface but also inside the film, especially in the case of porous materials, near the interface with the substrate. The content of fluorine atoms can also be confirmed. In addition, from the binding energy position by X-ray photoelectron spectroscopy analysis, it is confirmed that fluorine atoms are present in combination with atoms that are the main components of the porous body.

Prior to the step of plasma etching the mesostructure, it is preferable to have a step of modifying the surface of the mesostructure with an organic material. By having the step of modifying the surface of the mesostructure with an organic material, the aspect ratio (H / D) of the convex portion can be changed, and in many cases, the aspect ratio can be increased. Specifically, the step of modifying the surface with an organic material means a step of covering the surface with an organic material, a step of terminating at least a part of the surface with an organic material, etc., and is preferably used in the present invention. Is a step of terminating a part of the surface with an organic compound. Here, the term “termination” means that an organic functional group is fixed to the surface via a covalent bond, and can be confirmed by analysis of a binding state by an infrared absorption spectrum or photoelectron spectroscopy. In the step of terminating a part of the surface with an organic compound, the surface of the microstructure having a convex portion has a functional group that has a strong polarity, such as OH group and COOH group, and tends to increase the interfacial energy. This is particularly effective in the case where the surface is modified with an organic substance having an organic functional group that has the effect of weakening the polarity to reduce the interfacial energy. Examples of such organic functional groups include alkyl groups composed of C and H atoms, and fluorocarbons composed of C and F atoms. For this reason, the organic material preferably has an alkyl group. As such an organic compound, a substance having the above functional group and an active group which forms a bond by reacting with the surface of the mesostructure is preferable. For example, an alkoxide or a halide can be used. it can. The size of the organic compound used for modification is determined in view of the structure of the mesostructure, the diameter of the mesopores, and the like for the purpose of efficiently supplying the organic compound molecules into the mesostructure. Specifically, the organic compound used for modification is preferably a compound represented by the structure of SiX _y R _4-y , and the step of modifying the surface of the mesostructure with an organic compound is represented by the following general formula (1). It is preferable to be a step of exposing to an atmosphere containing a compound represented by the above or a step of applying a liquid containing the above compound.
SiX _y R _4-y General formula (1)
(In the formula (1), X represents a halogen or an alkoxy group, R represents an alkyl group, and y is an integer of 1 to 3.)

When y is 2 or 3, X may be the same or different. Further, when y is 1 or 2, it contains a plurality of alkyl groups, which may be the same or different. As the compound represented by the structure of SiX _y R _4-y , chlorotrimethylsilane is particularly preferably used. However, in the present invention, the compound used in the step of terminating at least a part of the surface with an organic compound is limited to this. It is not done. For the purpose of reacting the active group of the organic compound containing the functional group in the organic compound to be modified with the surface of the mesostructure, heating may be performed during the exposure. The heating temperature is appropriately optimized depending on the combination of the two. For example, when the mesostructured component is silica and the organic compound is chlorotrimethylsilane, the temperature is preferably in the range of room temperature to 100 ° C. After the exposure to the organic compound, for the purpose of removing excess organic compound, a step of washing the mesostructure with alcohol or the like may be added after the termination step.

  As a result of modifying the surface with such an organic compound, the interfacial energy is reduced, and as a result, the etching product tends to aggregate on the porous body film, the partial processing speed difference is further increased, and a high aspect ratio is obtained. The present inventors presume that a fine structure having convex portions can be obtained.

  Next, an example of a method for manufacturing the structure described in the second embodiment will be described.

  The structure manufacturing method described in the second embodiment includes, for example, a step of forming a mesostructure having mesopores, and depositing a substance having a material constituting a part of an etching chamber of a plasma etching apparatus. Forming a structure having a plurality of protrusions on the surface thereof by plasma etching the mesostructure.

  In addition, as described in the second embodiment, the plurality of convex portions described here have a cross-section when the convex portions are cut in a plane perpendicular to the direction from the bottom to the tip of the convex portion in the direction. It has a shape that becomes smaller along.

  The step of forming the mesostructure having mesopores is the same as the step of forming the mesostructure having mesopores in the structure manufacturing method example described in the first embodiment.

The step of forming a structure having a plurality of protrusions on the surface by plasma etching the mesostructure while depositing a substance having a material constituting a part of the etching chamber of the plasma etching apparatus on the inorganic oxide is an etching process. In this case, the etching is performed under such conditions that ions generated in the plasma sputter the member inside the etching apparatus and deposit a substance formed in an island shape on the surface of the etching member. The plasma density at the time of plasma etching is preferably a plasma density of 10 ¹¹ cm ⁻³ or more by a known high-density plasma generation method such as ICP, ECR, NLD, etc., and a low gas with a relatively simple apparatus configuration. An ICP method that can obtain a high-density (10 ¹² cm ⁻³ ) plasma under pressure is preferably used. The gas used for plasma etching is preferably a reactive gas, and more preferably a gas containing fluorine represented by SF ₆ and CxFy. Moreover, plasma is generated at a low pressure in the range of 0.05 Pa to 1 Pa using these gases, and the bias RF power density applied to the substrate is in the range of 0.12 W / cm ^{2 to} 0.40 W / cm ² . It is desirable to do. Under such low pressure and low substrate bias conditions, the potential difference between the generated high-density plasma and the member existing in the etching chamber is not significantly different from the potential difference between the substrate and the plasma. In addition to an increase in the ratio of incident ions, the mean free path of particles becomes long under low vacuum, and a substance (contamination) struck out by sputtering from the etching chamber constituent member is scattered on the substrate. The scattered contamination accumulates in the form of islands on the substrate (the deposit may contain an etching gas component in addition to contamination), and as a result of partially hindering the etching, the H / D is 2. A fine structure having a high aspect ratio of 0 or more is formed. The contamination including the members in the plasma etching apparatus is preferably a substance containing a metal element because it is desirable that the etching rate by the plasma etching is significantly smaller than that of the mesostructured material. In particular, since aluminum does not form a compound having a high vapor pressure with a fluorine-based gas (for example, a nonvolatile compound is formed like AlF3), the metal element is particularly preferably aluminum.

  In addition, it is preferable that the plasma etching is performed using a reactive gas and without using a mask.

  This method will be described in detail with reference to FIG. In FIG. 10, reference numeral 1001 denotes a substrate, and 1002 denotes a mesostructure. When manufacturing the structure described in the second embodiment in this manufacturing method, conditions are selected such that the contamination 1003 including the members constituting the etching chamber is deposited on the mesostructure in an island shape. To do. The contamination formed in this way has a high resistance to plasma etching, and the mesostructure in the non-formed part is selectively etched without almost etching the part where the contamination is formed. A large structure having a plurality of pillar-shaped convex portions 1004 having a shape in which the area of the cross section when cut in the direction from the bottom to the tip is reduced can be obtained. By adjusting the plasma etching conditions, a microstructure having a relatively uniform shape is obtained in the range where the average value of the height H of the pillar-shaped convex portions is 300 nm to 600 nm and the average interval p between the tops is 20 nm to 400 nm. I can do things. Each protrusion formed in this step takes a random arrangement with poor regularity as shown in FIG. 5C, and the in-plane density distribution of each protrusion is relatively uniform as shown in FIG. 7A. When used as an antireflection structure, a preferable configuration can be obtained. The distribution of the distance between the pillar-shaped protrusions is close to a normal distribution. By adjusting the plasma etching conditions, the average distance p between the columnar structures and the standard deviation σ in the distribution of the distance between the pillar-shaped protrusions. The ratio σ / p can be appropriately formed within the range of 0.1 <σ / p <0.5.

  In order to increase the aspect ratio of the convex portion of the structure described in any of the first to third embodiments, a material having a low etching rate can be used. This will be described in detail.

  First, a second layer made of a material having an etching rate smaller than that of the first layer is formed on the surface of the first layer made of a mesostructure having mesopores. A first plasma etching is performed on the second layer without using a mask to form a microstructure having a plurality of convex portions on the second layer. Next, a plurality of convex portions are formed in the first layer by performing second plasma etching through the microstructure formed in the second layer thus manufactured. Here, the fine structure formed of a plurality of convex portions formed in the second layer has a component contained in the material constituting the second layer and a reactive gas in the first plasma etching. It is formed by utilizing the difference in etching resistance between the locally bonded portion and the unbonded portion. The plurality of protrusions formed in the first layer after the second plasma etching has a cross-sectional area along the direction when the protrusions are cut along a plane perpendicular to the direction from the bottom toward the tip. It is a convex part which has a shape which becomes small.

  This method will be described in detail with reference to FIG. In FIG. 11, reference numeral 1101 denotes a substrate, and 1102 denotes a mesostructure. In the case of manufacturing the structure of the present invention in this manufacturing method, first, a layer 1103 of a material having an etching rate smaller than that of the mesostructure is formed on the mesostructure. Then, plasma etching is performed on the layer of the material having a low etching rate without using a mask to form a microstructure 1104 including a plurality of convex portions on the surface. Next, plasma etching of the mesostructure layer is performed through the microstructure 1104 thus manufactured, and a plurality of convex portions 1106 are formed in the mesostructure layer. In many cases, the plasma etching conditions for the material layer having a low etching rate are different from the plasma etching conditions for the mesostructure, and the gas type, gas pressure, plasma power, etc. are optimized. The above-described material having an etching rate smaller than that of the mesostructure means a difference in etching rate under conditions for etching the mesostructure. By this method, the microstructure 1104 composed of a plurality of convex portions formed on the surface of the material layer having a low etching rate has a structure in which the material and components contained in the reactive gas are locally bonded to each other. It is formed using the difference in etching resistance with the unbonded portion. When plasma etching is performed through a fine structure composed of a plurality of convex portions made of a material having a low etching rate, the mesostructure is formed with a portion of the material having a low etching rate remaining on the surface due to the difference in the etching rate. Etching progresses. Then, since the material 1105 having a small etching rate that remains in an island shape on the surface locally inhibits the plasma etching, the structure body 1106 of the present invention having a plurality of convex portions with a high aspect ratio can be obtained.

  In the above manufacturing method, since the material forming the first layer formed from the mesostructure is preferably transparent in the visible light region, a substance having a band gap of 2.5 eV or more and 10 eV or less is preferable. Any of silicon oxide, zirconium oxide or titanium oxide used is particularly preferably used. In addition, an inorganic oxide is preferably used as the material having an etching rate lower than that of the mesostructure, that is, the material constituting the second layer.

  In the structure manufacturing method described above, the reactive gas used for the first and second plasma etchings is preferably a gas containing fluorine.

  Further, by a method for manufacturing a structure having the steps of manufacturing the structure by such a method for manufacturing the structure, and transferring the shape of the structure to another substrate using the manufactured structure as a mold It is also possible to manufacture the structure according to the first embodiment and the structure according to the second embodiment.

  This manufacturing method will be described with reference to FIG. A layer 1202 of a material for forming a structure having a plurality of convex portions is formed on the base 1201, and plasma etching is used as a processing means, and any one of the first to third implementations is performed by any of the methods described above. A structure 1203 having a plurality of convex portions is formed. Next, a material 1204 is formed so as to completely fill the structure body 1203, and then the other base body 1205 is closely attached. The material and the forming method of the material 1204 are not particularly limited as long as the shape of the structure described in any of the first to third embodiments can be accurately transferred. For example, a cast resin having fluidity, an inorganic material precursor cast having fluidity, a vacuum film formation method, a chemical vapor deposition method, and a layer-by-layer film formation method are preferably used. Finally, when the structure 1203 having a plurality of protrusions that is first manufactured is removed, a structure corresponding to a negative when the structure manufactured first is positive is transferred onto the substrate 1205 that is formed last. In addition, a fine structure is formed. The structure described in any one of the first to third embodiments is transcribed to produce a structure having a complementary structure that does not completely match the above description, for example, even when an additional step is included. Needless to say, it is included in the present invention. For example, in order to retain the fine structure of the material 1204 even after 1203 is removed, the additional process has fluidity in the process of taking a mold 1203 before removing the structure 1203 having a plurality of protrusions. This is a step of hardening the material 1204 that has been formed.

  As described above, the structure manufactured by this manufacturing method corresponds to a negative when a structure formed by plasma etching is positive. The structure corresponding to this negative has a structure complementary to the structure formed by plasma etching, but when this negative structure is used as a mold and the transfer process is performed again, the structure of the first A structure having the same positive structure can be obtained. A manufacturing method for such a structure includes a step of transferring a shape of the structure to another base using a structure having a plurality of convex portions, which is manufactured using plasma etching, as a mold, This is a method for manufacturing a structure, which has a step of transferring the structure produced by transferring to the other substrate as a mold to another member (substrate).

  Further, an optical element having a base and an antireflection film is formed on the surface of the base by forming the structure by the method described in the method for manufacturing the structure described in the first to third embodiments. A member can be manufactured.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
Example 1 describes an example in which a fine structure is formed on a silica mesostructure film formed on a quartz glass substrate to provide an optical member provided with an antireflection structure. In FIG. 1, the structure of this example is a case where the substrate 14 is quartz, the silica mesostructures 11 and 15, and the convex portions formed of the silica mesostructures are 12.

  First, the manufacturing method of the optical member of a present Example is demonstrated later on along FIG.

(1-1) Substrate Preparation A quartz glass substrate was prepared as the substrate 14.

(1-2) Silica Mesostructure Film Formation (1-2-1) Precursor Solution Preparation of Silica Mesostructure Film The mesostructure precursor solution was added with ethanol, 0.01M hydrochloric acid and tetraethoxysilane and mixed for 20 minutes. The block solution is prepared by adding an ethanol solution of a block polymer and stirring for 3 hours. As a block polymer, ethylene oxide (20) propylene oxide (70) ethylene oxide (20) (hereinafter referred to as EO (20) PO (70) EO (20) (in parentheses are the number of repetitions of each block)) Is used. It is also possible to use methanol, propanol, 1,4-dioxane, tetrahydrofuran, or acetonitrile instead of ethanol. The mixing ratio (molar ratio) is tetraethoxysilane: 1.0, HCl: 0.0011, water: 6.1 ethanol: 8.7, and block polymer: 0.0096. The solution is appropriately diluted and used for the purpose of adjusting the film thickness.

(1-2-2) Formation of Silica Mesostructured Film A dip coat is performed on the washed quartz glass substrate 14 at a pulling rate of 0.5 mms ⁻¹ using a dip coater. After the film formation, the silica mesostructured film 15 was formed by holding in a constant temperature and humidity chamber at 25 ° C. and a relative humidity of 40% for 2 weeks and then at 80 ° C. for 24 hours. In the silica mesostructured film produced in this example, the EO (20) PO (70) EO (20), which is an organic substance, is held in the mesopores. When this silica mesostructure film cross section was observed with a scanning electron microscope, it was found that in the film produced in this example, cylindrical mesopores with a uniform diameter were periodically arranged in a honeycomb shape. . The periodic arrangement of mesopores in this film could be confirmed by the fact that a diffraction peak corresponding to a structural period of 8.0 nm can be confirmed by X-ray diffraction analysis.

(1-3) Plasma etching An ICP type plasma etching apparatus (manufactured by samco; high density plasma ICP etching apparatus: RIE-101iP) is used for the silica mesostructured film formed on the quartz glass substrate 14 under the following conditions. Then, plasma etching was performed to form convex portions 12.
Reactive gas: C ₃ F ₈
Gas flow rate: 20sccm
Pressure: 3Pa
ICP power: 500W
Bias power: 20W
Etching time: 9 minutes A plurality of conical convex portions are formed adjacent to each other on the surface of the mesostructured silica film after plasma etching, and the average values of the numerical values shown in the schematic diagram of FIG. A microstructure having a convex portion on the surface such that = 150 nm, Θ = 30 degrees, p = 100 nm, T = 60 nm, and H / D = 1.5 was obtained. Here, the density of the convex portions was estimated to be 3.1 × 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the convex portions is a normal distribution with σ = 32 nm, and σ / p is 0.32.

  For each value, image processing is performed on a cross-sectional photograph of the electron microscope for Θ, H, T, and D, and a planar photograph of the electron microscope for p and density, and the coordinates of the tip position of each convex portion are obtained. Calculated. Note that H can also be calculated by using an atomic force microscope, and it has been confirmed that it can be matched with the value obtained from the electron microscope image. These values are obtained by taking 20 electron micrographs with a visual field size of 1 μm within the region where the fine structure is formed, so that there is no bias in the region, and calculating the average value of each value. .

  After the plasma etching, the fine structure 11 was subjected to composition analysis in the depth direction of the film by X-ray photoelectron spectroscopy. As a result, fluorine atoms were contained in the fine structure 11, and the amount thereof was averaged by the Si atomic ratio. The value was 25%. In addition, it is confirmed from the binding energy position by X-ray photoelectron spectroscopy that fluorine atoms are present in combination with Si atoms. This indicates that etching progressed while fluorine was contained in the mesostructured silica film.

  Here, as a comparison, when a dense silica film having no pores is used and plasma etching is performed under the same conditions as in this step, no protrusions are formed on the surface (H = 5 nm or less), and the depth of the film Fluorine atoms are not detected in the vertical direction. Even when a silica mesostructure film is used, when Ar gas is used for plasma etching, no convex portion is formed on the surface (H = 5 nm or less), and the film is derived from an etching gas in the depth direction of the film. Argon atoms are not detected.

This means that in this step of forming a plurality of convex portions only by plasma etching, the material is a mesostructure having mesopores, and the reactive gas that reacts with the material forming the mesostructure in the etching step. It is shown that it is important for the formation of the structure of the present invention to advance the etching while containing the gas component in the mesostructure.
As described above, the antireflection structure 11 was formed on the quartz glass substrate 14.

(1-4) Measurement of reflectance The reflectance is measured by causing light to be vertically incident on the quartz glass substrate formed in Example 1 and having a structure having a plurality of convex portions using a halogen lamp. The measurement is performed by measuring the reflected light from the surface (the side on which the silica mesostructure film having a plurality of convex portions is present). When the average reflectance in the light wavelength range of 400 nm to 700 nm is calculated, the reflectance of the substrate surface produced in Example 1 is 1.5%. For comparison, when the reflectance of a quartz glass substrate without an antireflection structure is measured by the same method, it is 5.0%, and it is confirmed that the reflectance is reduced by the antireflection structure produced in Example 1. The Thereby, as shown in the present Example, it was shown that the structure of the present invention having a plurality of convex portions having a meso structure functions as an antireflection film.

(Example 2)
Example 2 describes an example in which a structure having a plurality of fine convex portions is formed on a mesoporous silica film formed on a quartz glass substrate and an antireflection structure is provided. In FIG. 1, the structure of this example is a case where the substrate 14 is quartz, the mesoporous silica is 11 and 15, and the convex portions formed of mesoporous silica are twelve.

  A mesostructured silica thin film was formed on the quartz glass substrate 14 by the same method as (1-1) to (1-2) of Example 1 ((2-1) to (2-2-2)).

(2-2-3) Porous formation The formed mesostructured film was baked at 400 ° C. for 4 hours in an air atmosphere in a baking furnace to remove organic components held in the pores as a mold. A mesoporous silica film 15 was obtained. From the transmission electron microscope analysis of the obtained film, it was found that the mesoporous silica film produced in this example had cylinder-shaped mesopores with a uniform diameter periodically arranged in a honeycomb shape. The periodic arrangement of mesopores in this film could be confirmed by the fact that a diffraction peak corresponding to a structural period of 6.0 nm can be confirmed in X-ray diffraction analysis.

(2-3) Plasma etching An ICP type plasma etching apparatus (manufactured by Samco; high density plasma ICP etching apparatus: RIE-101iP) is used for the mesoporous silica film 15 formed on the quartz glass substrate 14 under the following conditions. Plasma etching was carried out.
Reactive gas: SF ₆ gas Gas flow rate: 20 sccm
Pressure: 3Pa
ICP power: 100W
Bias power: 100W
Etching time: 2 minutes A plurality of conical convex portions are formed adjacent to each other on the surface of the mesoporous silica film after plasma etching, and the average values of the numerical values shown in the schematic diagram of FIG. A microstructure having a convex portion on the surface such that 60 nm, Θ = 30 degrees, p = D = 50 nm, T = 60 nm, and H / D = 1.2 was obtained. The density of the protrusions was estimated to be 6.5 × 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the convex portions is a normal distribution with σ = 14 nm, and σ / p is 0.28.

After the plasma etching, the microstructure 11 was subjected to composition analysis in the depth direction of the film by X-ray photoelectron spectroscopy. As a result, it was found that fluorine atoms were contained up to the vicinity of the interface with the quartz glass substrate 14, The amount was an average of 50% in terms of Si atomic ratio. In addition, it is confirmed from the binding energy position by X-ray photoelectron spectroscopy that fluorine atoms are present in combination with Si atoms. This indicates that the etching progressed while fluorine was contained in the pores of the mesoporous silica film. In the structure produced in this example in which a plurality of protrusions were formed on the mesoporous silica film from which the organic component used as the template was removed, the plurality of protrusions were formed on the silica mesostructured film with the organic substance remaining as the template remaining. The amount of fluorine contained was greater than that of the formed structure produced in Example 1. In addition, compared with Example 1, the structure of the present invention could be formed in a shorter plasma etching time.
As described above, the structure 11 having a plurality of convex portions of the present invention was formed on the quartz glass substrate 14.

(2-4) Measurement of reflectance The reflectance is measured by the same method as (1-4) of Example 1. The reflectance of the quartz glass formed on the surface of the structure body of the present invention formed in Example 2 is 2.5%, and the reflectance is reduced compared to the reflectance of the quartz substrate on which the structure body is not formed. ing. From this, it was shown that the structure of the present invention composed of mesoporous silica produced in this example functions as an antireflection film.

(Example 3)
Example 3 describes an example in which a fine structure is formed on a titania mesostructure film formed on a quartz glass substrate to provide an optical member provided with an antireflection structure. In FIG. 1, the structure of this example is a case where the substrate 14 is quartz, the titania meso structure 11 and 15, and the convex portion formed of the titania meso structure is 12.

(3-1) A quartz glass substrate was prepared as the substrate 14.
(3-2) Formation of titania meso structure film precursor (3-2-1) Preparation of titania meso structure film precursor solution The precursor solution of titania meso structure film was prepared by mixing a block polymer with an aqueous solution in which 12M hydrochloric acid and tetraethoxy titanium were mixed. It is prepared by adding a butanol solution of and stirring for 3 hours. As the block polymer, the same EO (20) PO (70) EO (20) used in Examples 1 and 2 was used. The mixing ratio (molar ratio) is tetraethoxytitanium: 1.0, hydrochloric acid: 2.0, water: 6.0, block polymer: 0.013, butanol: 9.0. The solution is appropriately diluted and used for the purpose of adjusting the film thickness.

(3-2-2) Formation of Titania Mesostructure Film A titania mesostructure film of this example is formed by dropping the prepared solution onto the cleaned quartz glass substrate 14 and performing spin coating. The spin coating is performed for 15 seconds under the conditions of 25 ° C., relative humidity of 40%, and substrate rotation speed of 3000 rpm. After film formation, the titania mesostructure film 15 is formed by holding in a constant temperature and humidity chamber at 25 ° C. and a relative humidity of 95% for 30 hours. The formed titania mesostructure film 15 has a thickness of about 550 nanometers and a refractive index of 1.5 by ellipsometry. In the titania mesostructured film produced in this example, the EO (20) PO (70) EO (20), which is an organic substance, is held in the mesopores. When the cross section of the titania meso structure film is observed with a scanning electron microscope, it can be seen that in the film produced in this example, cylindrical mesopores having a uniform diameter are periodically arranged in a honeycomb shape. The periodic arrangement of mesopores in this film can be confirmed by confirming a diffraction peak corresponding to a structural period of 8.4 nm in X-ray diffraction analysis.

(3-3) Plasma Etching Using the same ICP type plasma etching apparatus as that used in Examples 1 and 2, plasma etching was performed on the mesostructured titania thin film 15 formed on the quartz glass substrate 14 under the following conditions. Apply.
Reactive gas: SF ₆
Gas flow rate: 20sccm
Pressure: 3Pa
ICP power: 100W
Bias power: 20W
Etching time: 7 minutes A plurality of conical convex portions are formed adjacent to each other on the surface of the titania mesostructured film after plasma etching, and the average values of the numerical values shown in the schematic diagram of FIG. A fine structure having convex portions on the surface such that = 80 nm, Θ = 25 degrees, p = 60 nm, T = 200 nm, and H / D = 1.33 was obtained. Here, the density of the convex portions was estimated to be 6.5 × 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the convex portions is a normal distribution with σ = 14 nm, and σ / p is 0.23.

  After the plasma etching, the microstructure 11 was subjected to composition analysis in the depth direction of the film by X-ray photoelectron spectroscopy. As a result, fluorine atoms were contained in the microstructure 11, and the amount thereof was 25 in terms of Ti atom. %. This indicates that etching progressed while fluorine was contained in the mesostructured titania film.

(3-4) Measurement of reflectance The reflectance is measured by the same method as (1-4) of Example 1. The reflectance of the quartz glass formed in Example 3 and having the structure of the present invention is 2%, and it is confirmed that the reflectance is reduced by the manufactured antireflection structure. From this, it is shown that the structure of the present invention composed of the titania meso structure manufactured in this example functions as an antireflection film.

(Example 4)
Example 4 describes an example in which a fine structure is formed on a zirconia mesostructure film formed on a quartz glass substrate to provide an optical member provided with an antireflection structure. In FIG. 1, the structure of this example is a case where the substrate 14 is quartz, the zirconia mesostructures 11 and 15, and the convex portions formed of zirconia mesostructures are 12.

(4-1)
A quartz glass substrate was prepared as the substrate 14.

(4-2) Zirconia Mesostructure Film Formation (4-2-1) Precursor Solution Preparation of Zirconia Mesostructure Film The zirconia mesostructure film precursor solution is prepared by mixing an aqueous solution containing 12M hydrochloric acid and zirconium chloride. It is prepared by adding a butanol solution of block polymer and stirring for 3 hours. As the block polymer, the same EO (20) PO (70) EO (20) as used in Examples 1 to 3 was used. The mixing ratio (molar ratio) is zirconium chloride: 1.0, hydrochloric acid: 2.0, water: 6.0, block polymer: 0.013, butanol: 9.0. The solution is appropriately diluted and used for the purpose of adjusting the film thickness.

(4-2-2) Formation of Zirconia Mesostructure Film A zirconia mesostructure film of this example is formed by dropping the prepared solution onto the washed quartz glass substrate 14 and performing spin coating. . The spin coating is performed for 15 seconds under the conditions of 25 ° C., relative humidity of 40%, and substrate rotation speed of 3000 rpm. After film formation, the film is kept in a constant temperature and humidity chamber at 25 ° C. and a relative humidity of 95% for 30 hours to form a zirconia mesostructure film 15. The film thickness of the formed zirconia mesostructure film 15 is approximately 400 nanometers. The refractive index is determined to be 1.4 by ellipsometry. In the zirconia mesostructured film produced in this example, the EO (20) PO (70) EO (20), which is an organic substance, is held in the mesopores. When the cross section of the zirconia mesostructure film is observed with a scanning electron microscope, it can be seen that cylindrical mesopores having a uniform diameter are periodically arranged in a honeycomb shape in the film. The periodic arrangement of mesopores in this film can be confirmed by confirming a diffraction peak corresponding to a structural period of 8.6 nm in X-ray diffraction analysis.

(4-3) Plasma etching Plasma etching is performed on the mesostructured zirconia thin film 15 formed on the quartz glass substrate 14 using the same ICP type plasma etching apparatus as used in Examples 1 to 3 under the following conditions. Implement.
Reactive gas: SF ₆
Gas flow rate: 20sccm
Pressure: 3Pa
ICP power: 100W
Bias power: 20W
Etching time: 7 minutes On the surface of the zirconia mesostructured film after plasma etching, a plurality of conical convex portions are formed adjacent to each other, and the average values of the numerical values shown in the schematic diagram of FIG. A microstructure having convex portions on the surface such that H = 60 nm, Θ = 30 degrees, p = 50 nm, T = 200 nm, and H / D = 1.2 was obtained. Here, the density of the convex portions was estimated to be 6.5 × 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the convex portions is a normal distribution with σ = 15 nm, and σ / p is 0.30.

  After the plasma etching, the microstructure 11 was subjected to composition analysis in the depth direction of the film by X-ray photoelectron spectroscopy. As a result, fluorine atoms were contained in the microstructure 11, and the amount thereof was 25 in terms of Zr atomic ratio. %. This indicates that etching progressed while fluorine was contained in the mesostructured zirconia film.

(4-4) Measurement of reflectance The reflectance is measured by the same method as (1-4) in Example 1. The reflectance of the quartz glass formed with the structure of the present invention manufactured in Example 4 is 2%, and it is confirmed that the reflectance is reduced by the manufactured antireflection structure. From this, it was shown that the structure of the present invention composed of the zirconia mesostructure produced in this example functions as an antireflection film.

(Example 5)
In Example 5, the structure of the present invention having a plurality of convex portions, which was produced on a glass substrate by the same method as in Example 1, was used as a mold, and the shape of the microstructure was formed into another member by molding. It describes about the structure of this invention by transferring, and the method of manufacturing the optical member using which. Hereinafter, the manufacturing method of the optical member of a present Example is demonstrated along FIG.

  The structure body 1203 of the present invention is manufactured on the quartz substrate 1201 by the same method as (1-1) to (1-3) of the first embodiment.

(5-4) Molding On the substrate on which the structure is formed, a 50 μm spacer is provided, and an ultraviolet curable resin 1204 (RC-C001: manufactured by Dainippon Ink and Chemicals) is dropped. Subsequently, the quartz glass substrate 1205 subjected to the coupling treatment is slowly brought into contact with the ultraviolet curable resin 1204 and then pressed and slowly pressed to prevent bubbles from entering, and the quartz glass substrate 1205 and the quartz substrate 1201 are pressed. The ultraviolet curable resin 1204 is uniformly filled between the microstructures 1203 formed in the above. Subsequently, the filled UV curable resin 1204 is cured by irradiating UV light having a central wavelength of 365 nm at 40 mW for 750 seconds, and then the cured product 1204 is peeled off from the surface of the fine structure 1203 so that the fine structure is formed on the quartz glass substrate 1205. A resin 1204 transferred to the surface is obtained. The transferred fine structure has a structure corresponding to the negative when the structure of the structure having a plurality of protrusions produced in Example 1 is positive.

(5-5) Measurement of reflectance The reflectance is measured by the same method as (1-4) of Example 1. In Example 5, the reflectance of the quartz glass formed using the above transfer process and having the structure of the present invention formed thereon is 4%. From the above, it is confirmed that the reflectance is reduced by the antireflection structure produced in this example. As a result, as shown in the present example, it is shown that the structure of the present invention having a plurality of convex portions having a meso structure functions as an antireflection film.

(Example 6)
In Example 6, the structure of the present invention having a plurality of convex portions produced on the quartz glass substrate in the transfer process in Example 5 was further used as a mold, and molded and transferred to another member. Thus, a method for manufacturing the structure of the present invention having the same shape as the structure manufactured in Example 1 will be described.

(6-4) Molding A structure corresponding to the negative of the structure manufactured in Example 1 and made of a photocurable resin on a quartz substrate by the same steps as in Example 5 (5-4). To form a structure having After depositing amorphous carbon as a release layer on the surface of this resin, an ultraviolet curable resin is dropped by the same method as in Example 5. Subsequently, in the same manner as described in Example 5, the quartz glass substrate subjected to the coupling treatment was slowly wetted onto the ultraviolet curable resin, and then pressure-bonded, and slowly pressed so that no bubbles entered, The ultraviolet curable resin is uniformly filled between the quartz glass substrate and the microstructure formed of the cured resin formed on the quartz substrate in Example 5. Following this, the filled ultraviolet curable resin was cured by irradiating ultraviolet rays with a central wavelength of 365 nm at 40 mW for 750 seconds, and then separating the two resins using the carbon release layer, and finely irradiating them on the quartz glass substrate. A resin whose structure is transferred to the surface is obtained. This transferred microstructure has a structure having a plurality of protrusions, which is substantially the same as the structure having a plurality of protrusions produced in Example 1 because the mold is repeated twice. doing.

(6-5) Measurement of reflectance The reflectance is measured by the same method as (1-4) of Example 1. In Example 6, the reflectance of the quartz glass formed using the two-step transfer process and formed with the structure of the present invention is 1.2%. From the above, it is confirmed that the reflectance is reduced by the antireflection structure produced in this example. As a result, as shown in the present example, it is shown that the structure of the present invention having a plurality of convex portions having a meso structure functions as an antireflection film.

(Example 7)
In Example 7, after forming a structure having a plurality of fine protrusions on a mesoporous silica film formed on an optical glass substrate, the structure and the optical glass substrate were introduced by introducing titania into the mesopores. An example in which an optical member having an antireflection ability is obtained by matching the refractive indexes of these will be described. In FIG. 1, the structure of this example is mesoporous silica in which the substrate 14 is optical glass, 11, 15, and the convex portion 12 is formed with titania in the mesopores.

  The manufacturing process of this example will be described with reference to FIG.

(7-1) Substrate Preparation An optical glass substrate having a refractive index of 1.6 is prepared as the substrate 14.

(7-2) Formation of mesoporous silica film A silica mesostructured film was formed on the optical glass substrate 14 by the same method as (1-1) to (1-2) of Example 1, and (2- The organic substance in the pores is removed by the same method as in 2-3) to obtain a mesostructure (mesoporous silica film) 15 having voids inside. From the transmission electron microscope analysis of the obtained film, it can be seen that the mesoporous silica film produced in this example has cylinder-shaped mesopores of uniform diameter periodically arranged in a honeycomb shape. The periodic arrangement of mesopores in this film can be confirmed by confirming a diffraction peak corresponding to a structural period of 6.0 nm in X-ray diffraction analysis. The film thickness is about 500 nm. The refractive index of mesoporous silica produced in this step is determined to be 1.22 by ellipsometry.

(7-3) Plasma etching Plasma etching is performed on the mesoporous silica film 15 formed on the optical glass substrate 14 under the following conditions using the same ICP type plasma etching apparatus as used in Examples 1 to 6. .
Reactive gas: SF ₆ gas Gas flow rate: 20 sccm
Pressure: 3Pa
ICP power: 100W
Bias power: 100W
Etching time: 2 minutes A plurality of conical convex portions 12 are formed adjacent to each other on the surface of the mesoporous silica film after plasma etching, and the average values of the numerical values shown in the schematic diagram of FIG. A fine structure 11 having convex portions on the surface such that = 60 nm, Θ = 30 degrees, p = 50 nm, T = 80 nm, and H / D = 1.2 is obtained. A scanning electron micrograph of the formed microstructure is shown in FIG. 13 (a) is a photograph of the cross section, and 13 (b) is a photograph of the surface. The density of the convex portions is estimated to be 6.5 × 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the convex portions is a normal distribution with σ = 14 nm, and σ / p is 0.28.

  The microstructure 11 after the plasma etching was subjected to composition analysis in the depth direction of the film by X-ray photoelectron spectroscopy. As a result, it was found that fluorine atoms were contained up to the vicinity of the interface with the optical glass substrate 14. As can be seen, the amount is 50% in terms of Si atomic ratio. In addition, it is confirmed from the binding energy position by X-ray photoelectron spectroscopy that fluorine atoms are present in combination with Si atoms. This indicates that etching progressed while fluorine was contained in the mesoporous silica film.

(7-4) Inorganic material introduction into mesopores Subsequently, titania is introduced into the pores of mesoporous silica using a low pressure chemical vapor deposition (CVD) apparatus as shown in FIG. A precise structure is obtained to obtain a structure. In FIG. 14, 1401 is a vacuum vessel, 1402 is a test tube containing a precursor, 1403 is a needle valve, 1404 is a main valve, 1405 is a turbo molecular pump, 1406 is a dry scroll pump, 1407 is a vacuum gauge, and 1408 is a substrate. It is a holder.

As a pretreatment for CVD, an optical glass substrate formed by the step (7-3) and having a microstructure formed of mesoporous silica is baked at 400 ° C. for 4 hours in an air atmosphere, and then the substrate in the vacuum vessel 1401 After setting in a holder and exhausting to 2 × 10 ⁻⁵ Pa, heating is performed at 300 ° C. for 3 hours to remove surface adsorbed water and clean the surface.

  After returning the substrate to room temperature, titanium isopropoxide is introduced into the vacuum container 1401 until a pressure of 5 Pa is reached, and low pressure CVD is performed. In this CVD process, silanol groups present on the mesoporous surface of mesoporous silica react with titanium isopropoxide to form Si—O—Ti bonds.

After 7 hours, the substrate is taken out from the vacuum chamber and analyzed in the depth direction from the surface of the microstructure to the substrate interface by X-ray photoelectron spectroscopy. It can be seen that Ti atoms have been introduced, and that Ti atoms have been introduced at a Ti / Si atomic ratio of about 73%. Incidentally, Ti atomic binding energy position based on X-ray photoelectron spectroscopy can be confirmed to be present as titanium oxide (titania) TiO _2. As a result of scanning electron microscope observation of the structure after CVD, no significant change was observed in the shape of the structure, and it was difficult to observe the pores, so titanium oxide was formed in the mesopores I understand that.

  In this embodiment, a structure after introducing titania is obtained by obtaining a calibration curve regarding the dependency of refractive index on titania introduction amount as shown in FIG. The amount of titania introduced is controlled so that the effective refractive index of the body is the same as the refractive index 1.6 of the optical glass used. For comparison, when the structure composed of mesoporous silica used in this example was subjected to CVD for 5 hours and 3 hours under the same conditions, the refractive indexes were 1.5 and 1.4, respectively. Thus, it is shown that the amount of titania introduced can be precisely controlled by the low pressure CVD method in this step, and the refractive index can be precisely controlled.

  As described above, this process shows that the refractive index of the structure having a plurality of convex portions of the present invention composed of mesoporous silica can be matched with the refractive index 1.6 of the substrate by introducing titania. .

(7-5) Measurement of reflectance The reflectance is measured by the same method as (1-4) of Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm is calculated, the reflectance of the optical glass formed with the structure of the present invention composed of mesoporous silica with titania introduced into the pores, prepared in this example. Is required to be 2%. As a comparison, a mesoporous material having a hollow mesopore was prepared by the same method as in (7-1) to (7-3) of this example, omitting the titania in-mesopore introduction step of (7-4). When the reflectance of the optical glass on which the microstructure of the present invention composed of silica is formed is measured, it is 4%, and it is confirmed that the reflectance is reduced by the effect of refractive index control.

(Example 8)
Example 8 describes an example in which titania introduction into the mesopores in the step (7-4) in Example 7 is performed by a layer-by-layer film forming method instead of low pressure CVD.

  From (7-1) to (7-3), in the same process as in Example 7, a structure having a plurality of irregularities made of mesoporous silica is produced.

(8-4) Inorganic material introduction into mesopores The introduction of titania into the mesopores and the precise control of the refractive index thereby are carried out using the same apparatus as used in Example 7.

As a pretreatment for layer-by-layer film formation, an optical glass substrate on which a fine structure made of mesoporous silica is formed is baked at 400 ° C. for 4 hours in an air atmosphere, and then set on a substrate holder in a vacuum container 1401 to 2 × 10. After exhausting to ⁻⁵ Pa, heating is performed at 300 ° C. for 3 hours to remove surface adsorbed water and clean the surface.

After returning the substrate to room temperature, titanium isopropoxide was introduced into the vacuum vessel 1401 until the pressure reached 2 Pa, held for 30 minutes, evacuated to 1 × 10 ⁻⁴ Pa again, and then the vacuum pump valve 1404 was closed. Open the chamber to atmospheric pressure and return to normal pressure. After evacuating again to 2 × 10 ⁻⁵ Pa after 5 minutes, heating was performed at 300 ° C. for 1 hour, and titanium isopropoxide was again introduced until the pressure of 2 Pa was reached with the substrate temperature lowered to room temperature, and 30 minutes. Hold.

  In this step, silanol groups present on the mesoporous surface of mesoporous silica in the first titanium isopropoxide introduction step react with titanium isopropoxide to form Si—O—Ti bonds. In the next air release step, moisture in the air reacts with titanium isopropoxide bonded to silanol to form Ti-OH bonds. Furthermore, in the next titanium isopropoxide introduction step, the Ti—OH group reacts with titanium isopropoxide to form a Ti—O—Ti bond.

  Therefore, in this step, it is possible to form titania on the inner wall of one layer of mesopores by repeating titanium isopropoxide introduction → atmospheric release → heating → cooling → titanium isopropoxide introduction. For this reason, this method is called a layer-by-layer deposition method. This method is also called a surface sol-gel method, and is a method classified as a kind of sol-gel method.

  Under the conditions of this example, the refractive index of the structure having a plurality of convex portions of the present invention composed of mesoporous silica is obtained by repeating the titanium isopropoxide introduction step three times including the first titanium isopropoxide introduction. Can be matched to the refractive index of the substrate 1.6 by introducing titania. When the refractive indexes of the substrates are different, the refractive index of the structure of the present invention can be precisely controlled by adjusting the number of repetitions.

When the depth direction analysis from the surface of the fine structure to the substrate interface direction is performed by X-ray photoelectron spectroscopy, the structure of this example of the example is relatively uniformly distributed from the fine structure surface to the vicinity of the substrate interface. It can be seen that about 73% of atoms are introduced in terms of Si atomic ratio. Incidentally, Ti atomic binding energy position based on X-ray photoelectron spectroscopy can be confirmed to be present as titanium oxide (titania) TiO _2. As a result of scanning electron microscope observation of the structure after CVD, no significant change was observed in the shape of the structure, and it was difficult to observe the pores, so titanium oxide was formed in the mesopores I understand that.

(8-5) Reflectance measurement The reflectance is measured by the same method as (1-4) in Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm is calculated, the reflectance of the optical glass formed with the structure of the present invention composed of mesoporous silica with titania introduced into the pores, prepared in this example. Is required to be 2%. This is the same value as that produced by the low pressure CVD of Example 7. As described in Example 7, the reflectivity of the optical glass on which the microstructure of the present invention composed of mesoporous silica having hollow mesopores was measured was 4%. It is confirmed that the reflectance is reduced by the effect of the rate control.

Example 9
Example 9 describes an example in which the introduction of titania into the mesopores in step (7-4) in Example 7 is performed by a liquid phase method based on a sol-gel method instead of low pressure CVD.

  From (7-1) to (7-3), in the same process as in Example 7, a structure having a plurality of irregularities made of mesoporous silica is produced.

(9-4) Inorganic material introduction into mesopores In a nitrogen gas atmosphere, a titanium isopropoxide n-decane solution (80 wt%) is prepared, and has a plurality of irregularities composed of the mesoporous silica. The substrate on which the body is formed is immersed at room temperature for 1 hour. Subsequently, the substrate on which the structure was formed was washed with n-decane and dried, then placed in distilled water, held for 24 hours, dried at 150 ° C. for 24 hours, and further subjected to atmospheric firing at 400 ° C. for 2 hours. , Titania is introduced into the pores of the mesoporous silica structure.

  When the depth direction analysis from the microstructure surface to the substrate interface direction is performed by X-ray photoelectron spectroscopy on the structure of this example, the Ti atoms are relatively uniform with a Ti / Si atomic ratio of about 64%. It can be seen that it has been introduced. The effective refractive index of the structure after the introduction of titania produced in this example is 1.56, and the difference from the refractive index of 1.60 of the optical glass substrate is 0.04.

(9-5) Measurement of reflectance The reflectance is measured by the same method as (1-4) of Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm is calculated, the reflectance of the optical glass formed with the structure of the present invention composed of mesoporous silica with titania introduced into the pores, prepared in this example. Is determined to be 2.2%. As described in Example 7, when the reflectance of the optical glass formed with the microstructure of the present invention composed of mesoporous silica having hollow mesopores was measured, it was 4%, and titania was added to the mesoporous silica structure. By reducing the difference in refractive index from the substrate by introducing the same, a reduction in reflectance due to the effect of refractive index control is also confirmed in this embodiment.

(Example 10)
In Example 10, a fine structure is formed on a titania mesostructure film formed on an optical glass substrate, and silica is introduced into the mesopores, and then organic components are removed, whereby the structure and the optical glass substrate are refracted. An example in which the optical member having antireflection ability is obtained by matching the rate will be described. In FIG. 1, the structure of this example is a mesoporous titanium oxide in which the substrate 14 is optical glass, 11, 15, and the convex portions 12 are formed by forming silica in mesopores.

(10-1) Substrate Preparation An optical glass substrate having a refractive index of 1.7 is prepared as the substrate 14.

(10-2) Formation of titania mesostructure film Basically the same as described in Example 3 by the same steps as described in (3-2-1) to (3-2-2) of Example 3. A titania mesostructured film having the following structure is prepared.

(10-3) Plasma etching A structure having a plurality of fine protrusions basically the same as those described in Example 3 by the same plasma etching process described in Example 3 (3-3). Is made.

(10-4) Introduction of silica into mesopores A substrate prepared as described above and having a titania mesostructure formed with a structure having a plurality of convex portions is placed in an autoclave having a volume of 70 ml, and a container After putting 3 ml of tetramethyl orthosilicate (TMOS) in the inside, it is sealed and exposed to TMOS vapor at 50 ° C. for 2 hours to introduce silica into the mesopores of the titania mesostructured film. The template block copolymer is retained in the mesopores of the titania mesostructured film exposed to the vapor of TMOS. Even in this state, silica is formed in the pores by the method described in this example. The present inventors have found that. After this TMOS vapor treatment, the substrate on which the structure is formed is taken out of the autoclave and baked at 350 ° C. in the atmosphere for 4 hours to remove the block copolymer of the template.

  When X-ray photoelectron spectroscopy is used to analyze the depth direction from the surface of the microstructure manufactured in this example to the interface of the optical glass substrate, Si atoms in the film are about 49% in terms of Si / Ti atomic ratio. You can see that it has been introduced.

(10-5) Measurement of reflectance The reflectance is measured by the same method as (1-4) of Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm was calculated, the reflectance of the optical glass formed with the structure of the present invention composed of mesoporous titania with silica introduced into the pores, produced in this example. Is required to be 2%. As a comparison, it was prepared by the same method from (10-1) to (10-3) of this example, and the step of introducing silica into the mesopores of (10-4) was omitted. The reflectance of the optical glass on which the microstructure of the present invention composed of mesoporous titania having hollow mesopores obtained by baking for a time was measured was 4%, and the reflectance was due to the effect of refractive index control. It is confirmed that it is reduced.

(Example 11)
In Example 11, a microstructure is formed on a zirconia mesostructure film formed on an optical glass substrate, silica is introduced into the mesopores, and then organic components are removed to thereby remove the structure and the optical glass substrate. An example in which the refractive index is matched and an optical member having antireflection ability is described. In FIG. 1, the structure of this example is mesoporous zirconium oxide in which the substrate 14 is optical glass, 11, 15, and the convex portions 12 are formed by forming silica in mesopores.

(11-1) Substrate Preparation An optical glass substrate having a refractive index of 1.7 is prepared as the substrate 14.

(11-2) Formation of zirconia mesostructured film Basically as described in Example 4 by the same steps as described in (4-2-1) to (4-2-2) of Example 4. A zirconia mesostructured film having the same structure is produced.

(11-3) Plasma etching A structure having a plurality of fine protrusions basically the same as those described in Example 4 by the same plasma etching process as described in (4-3) of Example 4. Is made.

(11-4) Introduction of silica into pores A substrate prepared as described above and having a zirconia mesostructure formed with a structure having a plurality of convex portions is placed in an autoclave having a volume of 70 ml. After putting 3 ml of TMOS in the container, the container is sealed and exposed to TMOS vapor at 50 ° C. for 2 hours to introduce silica into the mesopores of the zirconia mesostructured film. The block copolymer of the template is retained in the mesopores of the zirconia mesostructured film exposed to the vapor of TMOS. Even in this state, silica is formed in the pores by the method described in this example. The present inventors have found that. After this TMOS vapor treatment, the substrate on which the structure is formed is taken out of the autoclave and baked at 350 ° C. in the atmosphere for 4 hours to remove the block copolymer of the template.

  When X-ray photoelectron spectroscopy is used to analyze the depth direction from the surface of the microstructure fabricated in this example to the interface of the optical glass substrate, Si atoms in the film are about 49% in terms of Si / Zr atomic ratio. You can see that it has been introduced.

(11-5) Measurement of reflectance The reflectance is measured by the same method as (1-4) of Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm was calculated, the reflectance of the optical glass formed with the structure of the present invention composed of mesoporous zirconia having silica introduced into the pores, produced in this example. Is required to be 2%. As a comparison, the same steps as (11-1) to (11-3) of this example were performed, and the step of introducing silica into the mesopores of (11-4) was omitted. The reflectance of the optical glass on which the microstructure of the present invention composed of mesoporous zirconia having hollow mesopores obtained by baking for a time was measured was 4%, and the reflectance was due to the effect of controlling the refractive index. It is confirmed that it is reduced.

(Example 12)
In Example 12, the mesoporous silica film formed on the optical glass substrate is modified with an organic compound and then subjected to plasma etching to form a structure having a plurality of fine protrusions with a high aspect ratio, Further, an example will be described in which titania is introduced into the mesopores, thereby matching the refractive index of the structure and the optical glass substrate to obtain an optical member having antireflection ability. The basic structure of the structure manufactured by this example is the same as that described in Example 7, but the aspect ratio of the structure formed is different.

(12-1) Substrate Preparation An optical glass substrate having a refractive index of 1.6 is prepared as the substrate 14.

(12-2) Formation of mesoporous silica thin film A silica mesostructured film is formed on the optical glass substrate 14 by the same method as (1-1) to (1-2) of Example 1, and (2- Organic matter in the pores is removed by the same method as in 2-3) to obtain the mesoporous silica film 15. From the transmission electron microscope analysis of the obtained film, it can be seen that the mesoporous silica film produced in this example has cylinder-shaped mesopores of uniform diameter periodically arranged in a honeycomb shape. The periodic arrangement of mesopores in this film can be confirmed by confirming a diffraction peak corresponding to a structural period of 6.0 nm in X-ray diffraction analysis. The film thickness is about 500 nm. The refractive index of mesoporous silica produced in this step is determined to be 1.22 by ellipsometry.

(12-3) Surface Modification with Organic Compound Trimethylchlorosilane was dropped onto the mesoporous silica film formed on the optical glass substrate, and spin coating was performed at a rotational speed of 2000 rpm for 30 seconds. Thereafter, the substrate was washed with ethanol. Comparing the infrared absorption spectra before and after this treatment, after the treatment, the absorption peak at 3740 cm ⁻¹ corresponding to the isolated silanol group (Si—OH) is decreased compared with that before the treatment, and the methyl group (—CH ₃ ) is observed. A corresponding 2960 cm ⁻¹ absorption peak was observed. In addition, when a composition analysis in the depth direction of the mesoporous silica film was performed by X-ray photoelectron spectroscopy, carbon atoms that were not observed before the treatment were observed up to the vicinity of the interface with the optical glass substrate after the treatment. It was. From these things, it was confirmed that the surface of the mesoporous mesoporous silica (including the external surface) was terminated with a trimethylsilyl group by this treatment.

(12-4) Plasma etching Plasma etching is performed on the mesoporous silica film subjected to the above surface treatment under the following conditions using the same ICP type plasma etching apparatus as used in Examples 1-11.
Reactive gas: C ₃ F ₈
Gas flow rate: 20sccm
Pressure: 3Pa
ICP power: 500W
Bias power: 50W
Etching time: 90 seconds On the surface of the mesoporous silica film after plasma etching, a plurality of conical convex portions were formed adjacent to each other, and a microstructure having a plurality of fine convex portions was obtained. Scanning electron micrographs of the microstructure are shown in FIG. 15A (cross-sectional photograph) and FIG. 15B (surface image taken at a substrate tilt angle of 75 degrees). By this plasma etching, the average values of the numerical values shown in the schematic diagram of FIG. 1B are H = 320 nm, Θ = 20 degrees, p = D = 70 nm, T = 200 nm, and H / D = 4.6, respectively. A fine structure having such convex portions on the surface was obtained. Here, the density of the convex portions was estimated to be 5.2 × 10 ¹⁰ pieces / cm ² . The distribution of the interval between the convex portions is a normal distribution with σ = 30 nm, and σ / p is 0.42. From this, it was shown that the aspect ratio of the convex part formed dramatically can be improved by surface modification with an organic substance before the plasma treatment of the mesoporous silica film.

  About the microstructure after plasma etching, composition analysis in the depth direction of the film by X-ray photoelectron spectroscopy revealed that fluorine atoms were contained up to the vicinity of the interface with the optical glass substrate, The amount was an average value of about 50% in terms of F / Si atomic ratio. In addition, it is confirmed from the binding energy position by X-ray photoelectron spectroscopy that fluorine atoms are present in combination with Si atoms. This indicates that etching progressed while fluorine was contained in the mesoporous silica film. Such a structure could not be formed by plasma etching using Ar gas.

(12-5) Inorganic material introduction into mesopores Subsequently, titania is introduced into the mesopores of the structure formed from the mesoporous silica produced in the above step. The introduction of titania was performed under the same conditions as used in (7-4) using the same reduced pressure CVD apparatus as used in (7-4) of Example 7. After 7 hours, the substrate is taken out from the vacuum chamber and analyzed by X-ray photoelectron spectroscopy in the depth direction from the surface of the microstructure to the substrate interface. It can be seen that Ti is introduced and about 73% of Ti atoms are introduced at a Ti / Si atomic ratio. In addition, it can confirm that Ti atom exists as TiO2 from the binding energy position by X-ray photoelectron spectroscopy analysis. The amount of titania introduced was converted to a pore filling rate of about 60%.

  This introduction amount is substantially the same as the introduction amount achieved in Example 7, and the refractive index of the structure of the present invention after the introduction of titania is about 1.6, which is the refractive index of the optical glass substrate used. Is almost equal to As described above, this process shows that the refractive index of the structure having a plurality of convex portions of the present invention composed of mesoporous silica can be matched with the refractive index 1.6 of the substrate by introducing titania. .

(12-6) Measurement of reflectance The reflectance is measured by the same method as (1-4) of Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm is calculated, the reflectance of the optical glass formed with the structure of the present invention composed of mesoporous silica with titania introduced into the pores, prepared in this example. Was determined to be 0.3%. For comparison, the reflectance of the optical glass substrate used in this example without an antireflection structure is 5% when measured by the same method. The reflectance is greatly reduced by the antireflection structure produced in this example. It was confirmed that FIG. 16 shows the wavelength dependency of the reflectance of the optical glass substrate on which the structure manufactured in this example is formed and the optical glass substrate on which the surface is not coated. As shown in this example, the mesoporous silica film on the optical glass substrate is subjected to organic modification and then subjected to plasma etching, so that the aspect ratio of the convex portions to be formed can be greatly improved. It was shown that a very low reflectance can be realized by introducing titania in a controlled amount and matching the refractive index of the substrate and the structure.

(Example 13)
In Example 13, a mesoporous silica film formed on a quartz substrate is modified with an organic compound and then subjected to plasma etching to form a structure having a plurality of fine protrusions with a high aspect ratio, An example will be described in which silica is introduced into the mesopores to match the refractive index of the structure and the quartz glass substrate to obtain an optical member having antireflection ability. In FIG. 1, the structure of this example is a mesoporous silica in which the substrate 14 is quartz glass, 11, 15, and the projections 12 are formed in the mesopores.

(13-1) Substrate Preparation A quartz glass substrate is prepared as the substrate 14.

(13-2) Formation of mesoporous silica thin film A mesoporous silica film having substantially the same structure as that produced in Example 12 is produced in the same manner as in (12-1) to (12-2) of Example 12.

(13-3) Surface modification with organic compound The same organic modification is applied in the same step as (12-3) of Example 12.

(13-4) Plasma Etching Using the same apparatus and the same conditions as in Example 12 (12-4), a structure substantially identical to the structure manufactured in Example 12 is produced.

(13-5) Inorganic material introduction into mesopores The substrate formed in the above process and having a structure having a plurality of convex portions was placed in an autoclave having a volume of 70 ml, and 3 ml of TMOS was placed in the container. After sealing, it was exposed to TMOS vapor for 2 hours at 50 ° C, followed by firing for 4 hours at 350 ° C in the atmosphere to form a structure in which silica was introduced into the mesopores of mesoporous silica. To do.

(13-6) Reflectance measurement The reflectance is measured by the same method as (1-4) in Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm is calculated, the reflectance of the quartz glass formed with the structure of the present invention composed of mesoporous silica with titania introduced into the pores, produced in this example. Is required to be 0.5%. For comparison, the reflectance of the quartz glass substrate used in this example without providing an antireflection structure is 5% when measured by the same method, and the reflectance is greatly reduced by the antireflection structure produced in this example. It is confirmed that As shown in this example, the mesoporous silica film on the quartz glass substrate is organically modified and then subjected to plasma etching, so that the aspect ratio of the formed convex portion can be greatly improved, and the pores It is shown that a very low reflectance can be realized by introducing silica in a controlled amount and taking a refractive index matching between the substrate and the structure.

(Example 14)
In Example 14, a mesoporous silica film having a large film thickness was produced on a quartz substrate, and a structure having a plurality of convex portions having a large aspect ratio was produced by performing plasma etching similar to Examples 12 and 13. Is described.

(14-1) Formation of Mesoporous Silica Film on Substrate A silica mesostructured film is formed on a quartz glass substrate by the same method as (1-1) to (1-2) in Example 1, and completely dried. After solidifying, the step (1-2) is repeated once more to obtain a silica mesostructured film having a film thickness of about 1000 nm. Thereafter, organic substances in the pores are removed by the same method as (2-2-3) in Example 2 to obtain a mesoporous silica film. From the transmission electron microscope analysis of the obtained film, it can be seen that the mesoporous silica film produced in this example has cylinder-shaped mesopores of uniform diameter periodically arranged in a honeycomb shape. The periodic arrangement of mesopores in this film can be confirmed by confirming a diffraction peak corresponding to a structural period of 6.0 nm in X-ray diffraction analysis.

(14-2) Surface modification with organic compound This mesoporous silica film is subjected to organic modification using trimethylchlorosilane in the same step as (12-3) of Example 12.

(14-3) Plasma Etching The modified mesoporous silica film is subjected to plasma etching under the following conditions using the same ICP type plasma etching apparatus as used in Examples 1-13.
Reactive gas: C ₃ F ₈
Gas flow rate: 20sccm
Pressure: 3Pa
ICP power: 500W
Bias power: 50W
Etching time: 200 seconds On the surface of the mesoporous silica film after plasma etching, a plurality of conical convex portions are formed adjacent to each other, and the average values of the numerical values shown in the schematic diagram of FIG. A microstructure having a convex portion on the surface such that 620 nm, p = 70 nm, D = 60 nm, T = 50 nm, and H / D = 10.3 is obtained. Here, the density of the convex portions was estimated to be 6.0 × 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the convex portions is a normal distribution with σ = 15 nm, and σ / p is 0.21.

  In this example, as described above, it is shown that a structure having an aspect ratio of 10 or more of the convex portion can be formed by increasing the film thickness of the initial mesoporous silica film and performing plasma etching after organic modification.

(Example 15)
In Example 15, a large mesoporous silica film was prepared on a quartz substrate, the surface was modified with chlorotributylsilane, and then plasma etching similar to that in Examples 12 and 13 was performed, whereby a plurality of large aspect ratios were obtained. An example in which a structure having a convex portion is manufactured will be described.

(15-1) Formation of Mesoporous Silica Film on Substrate After a silica mesostructure film having a film thickness of about 1000 nm is formed on a quartz substrate by the same process as (14-1) of Example 14, the same process is performed. Organic substances in the pores are removed to obtain a mesoporous silica film. The mesoporous silica film produced in this example has substantially the same structure as the mesoporous silica film produced in Example 14.

(15-2) Surface modification with organic compound Tributylchlorosilane is dropped on the above mesoporous silica film formed on a quartz glass substrate, spin-coated at a rotational speed of 2000 rpm for 30 seconds, and then the substrate is washed with ethanol. . The termination by the trimethylsilyl group on the surface of the mesoporous silica (including the external surface) of the mesoporous silica is confirmed by the infrared absorption spectrum as in Example 12.

(15-3) Plasma Etching The modified mesoporous silica film is subjected to plasma etching under the following conditions using the same ICP type plasma etching apparatus as used in Examples 1-14.
Reactive gas: C ₃ F ₈
Gas flow rate: 20sccm
Pressure: 3Pa
ICP power: 500W
Bias power: 50W
Etching time: 220 seconds On the surface of the mesoporous silica film after plasma etching, a plurality of conical convex portions are formed adjacent to each other, and the average values of the numerical values shown in the schematic diagram of FIG. A microstructure having a convex portion on the surface such that 550 nm, p = 90 nm, D = 90 nm, T = 50 nm, and H / D = 6.1 is obtained. Here, the density of the convex portions was estimated to be 6.0 × 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the convex portions is a normal distribution with σ = 15 nm, and σ / p is 0.21.

  This example shows that the aspect ratio of fine protrusions formed by plasma etching on a mesoporous silica film can be increased even when organically modified with an organic substance other than trimethylchlorosilane as described above. It is.

(Example 16)
In Example 16, a mesoporous silica film having a different pore structure is laminated on an optical glass substrate to form a structure having a plurality of fine protrusions, and then titania is introduced into the mesopores. Thus, an example in which the refractive index of the structure and the optical glass substrate is matched to obtain an optical member having antireflection ability will be described. In the configuration of the present example, the filling rate of titania into the mesopores decreases in the direction from the bottom to the tip of the convex portion, and as a result, the Ti / Si ratio decreases in the direction. . The structure of the structure manufactured in this example is similar to the structure of the structure manufactured in Example 7, but in Example 7, a single-structure mesoporous silica film is used. The present embodiment is different in that mesoporous silica films having different structures are laminated and used.

  In FIG. 1, the structure of this example is mesoporous silica in which a substrate 14 is optical glass, 11 and 15, and convex portions 12 are formed with titania in mesopores and layers of different pore structures are laminated. .

(16-1) Substrate Preparation A quartz glass substrate is prepared as the substrate 14.

(16-2) Formation of mesoporous silica thin film (16-2-1) Preparation of first silica mesostructure film Precursor solution for first silica mesostructure film according to the procedure of (1-2-1) of Example 1 Adjust. The solution composition is the following composition (molar ratio) having a higher ethanol concentration than that described in Example 1. Tetraethoxysilane: 1.0, HCl: 0.0011, water: 6.1 ethanol: 29.0, block polymer: 0.0096. The reason for increasing the amount of ethanol is to reduce the thickness of the first silica mesostructure. Using this solution, a first silica mesostructured film is produced on the quartz glass substrate by dip coating under the same conditions as in Example 1. The film thickness is required to be 90 nm. The first silica mesostructured film has the same structure as the silica mesostructured film produced in Example 1 except for the film thickness, and has a structure in which cylindrical mesopores having a uniform diameter are periodically arranged in a honeycomb shape. It is clear by observation with a scanning electron microscope that the periodic arrangement of mesopores in this film confirms a diffraction peak corresponding to a structural period of 8.0 nm in X-ray diffraction analysis. You can confirm that you can.

(16-2-2) Production of second silica mesostructured film On the first silica mesostructured film when the solidification of the silica in the first silica mesostructured film produced by the above process has sufficiently progressed. Second, a second silica mesostructured film having a different structure is produced. This production is also basically the same as in Example (1-2-1), but the solution composition (molar ratio) is as follows. Tetraethoxysilane: 1.0, HCl: 0.0011, water: 6.1 ethanol: 10.0, block polymer: 0.0096, ethylene glycol: 0.067. The inventors have already found that the periodic arrangement of mesopores in the silica mesostructured film formed is lost by the addition of ethylene glycol. Using this solution, a second silica mesostructure film is produced on the quartz glass substrate on which the first silica mesostructure film is formed by dip coating under the same conditions as in Example 1. The film thickness is required to be 400 nm.

(16-2-3) Making Porous An organic substance in the pores is removed by the same method as (2-2-3) in Example 2 to obtain a mesoporous silica film.

(16-3) Plasma Etching Using the same ICP type plasma etching apparatus as used in Examples 1 to 11 for the two-layered mesoporous silica film produced in the above process, plasma etching was performed under the following conditions. Apply.
Reactive gas: SF ₆
Gas flow rate: 20sccm
Pressure: 3Pa
ICP power: 100W
Bias power: 100W
Etching time: 2 minutes A plurality of conical convex portions were formed adjacent to each other on the surface of the mesoporous silica film after plasma etching, and a fine structure having a plurality of fine convex portions was obtained. By this plasma etching, the average values shown in the schematic diagram of FIG. 1B are H = 60 nm, Θ = 30 degrees, p = D = 50 nm, T = 60 nm, and H / D = 1.2, respectively. A microstructure having such a plurality of convex portions on the surface was obtained. Here, the density of the convex portions was estimated to be 5.0 × 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the convex portions is a normal distribution with σ = 14 nm, and σ / p is 0.28. The average distance from the substrate interface to the tip of the convex part is about 120 nm. This means that the convex part in the formed structure is based on the structure of the second mesoporous silica on the side half near the tip. It shows that the near side half has the structure of the first mesoporous silica. About the microstructure after plasma etching, composition analysis in the depth direction of the film by X-ray photoelectron spectroscopy revealed that fluorine atoms were contained up to the vicinity of the interface with the optical glass substrate, The amount was an average value of about 50% in terms of Si atomic ratio. In addition, it is confirmed from the binding energy position by X-ray photoelectron spectroscopy that fluorine atoms are present in combination with Si atoms. This indicates that etching progressed while fluorine was contained in the mesoporous silica film.

(16-4) Inorganic material introduction into pores Subsequently, titania is introduced into the mesopores of the structure formed from the mesoporous silica produced in the above step. The introduction of titania was performed under the same conditions as used in (7-4) using the same reduced pressure CVD apparatus as used in (7-4) of Example 7. After 7 hours, the substrate is taken out from the vacuum vessel and analyzed by X-ray photoelectron spectroscopy in the depth direction from the surface of the microstructure to the substrate interface, and the Ti / Si ratio is about 0.65 near the surface. The Ti / Si ratio is determined to be about 0.73 in the vicinity of the substrate, and it can be seen that the relative ratio of Ti is about 10% smaller in the vicinity of the surface. This depth direction analysis is performed by repeatedly performing ion sputtering and measuring the photoelectron spectrum each time. This difference is formed in the half of the convex portion on the substrate side in the pores of the second mesoporous silica film in which the structural periodicity of the mesopores is disturbed. This indicates that titania is less likely to be introduced compared to the pores of the first mesoporous silica film having mesopore structure periodicity. Actually, it is confirmed by observation with a transmission electron microscope that the filling rate of titania in the pores of the first mesoporous silica film is lower than the filling rate in the pores of the second mesoporous silica film. The present inventors consider that this is because, in the case of a pore structure having no structural periodicity, the precursor of titanium oxide hardly diffuses in the pores in the CVD process. The Ti / Si ratios 0.65 and 0.73 are 55% and 62%, respectively, in terms of titania filling rate.

  As described above, in the structure having a plurality of fine protrusions manufactured in this example, the titania filling rate into the mesopores decreases in the direction from the bottom to the tip of the protrusion. As a result, it is confirmed that the Ti / Si ratio decreases in the direction.

(16-5) Reflectance measurement The reflectance is measured by the same method as (1-4) of Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm was calculated, the structure of the present invention composed of two layers of mesoporous silica films having different structures, in which titania was introduced into the pores, prepared in this example. The reflectance of the formed quartz glass is required to be 1.8%. This reflectivity is lower than the reflectivity of the quartz substrate formed using the mesoporous silica having a single structure in Example 2 and having the structure having the same structure as that of this example. In this embodiment, the antireflection effect is further enhanced by reducing the filling rate of titania into the mesopores in the direction from the bottom to the tip of the protrusions in the structure of the present invention. Is confirmed.

(Example 17)
In Example 16, a mesoporous silica film having a different structural period and (pore diameter) was laminated on an optical glass substrate to form a structure having a plurality of fine protrusions, and then titania in the mesopores. An example will be described in which the refractive index of the structure and the optical glass substrate is matched by introducing the optical member to obtain an optical member having antireflection ability. In the configuration of the present example, the filling rate of titania into the mesopores decreases in the direction from the bottom to the tip of the convex portion, and as a result, the Ti / Si ratio decreases in the direction. . The structure of the structure manufactured in this example is similar to the structure of the structure manufactured in Example 16, but in Example 16, mesoporous silica films having different structures are stacked and used. On the other hand, the present embodiment is different in that mesoporous silica films having different structure periods and pore diameters are laminated.

(17-1) Substrate Preparation A quartz glass substrate is prepared as the substrate 14.

(17-2) Formation of mesoporous silica thin film (17-2-1) Preparation of first silica mesostructure film Precursor solution for first silica mesostructure film according to the procedure of (1-2-1) of Example 1 Adjust. Here, a surfactant Brij56 (trade name, manufactured by Aldrich, = polyoxyethylene-10-cetyl ether) different from that used in Example 1 is used as a template. This precursor solution is prepared by adding a 2-propanol solution of Brij56 to a solution obtained by adding 2-propanol, 0.01M hydrochloric acid and tetraethoxysilane and mixing for 20 minutes, and stirring for 3 hours. The composition (molar ratio) of the solution is tetraethoxysilane: 1.0, block polymer: 0.080, 2-propanol: 25, hydrochloric acid: 0.0011, and water: 6.1. Using this solution, a first silica mesostructured film is produced on the quartz glass substrate by dip coating under the same conditions as in Example 1. The film thickness is required to be 100 nm. In the first silica mesostructured film, it is clear by observation with a scanning electron microscope that cylindrical mesopores having a uniform diameter are periodically arranged in a honeycomb shape. The periodic arrangement of mesopores in this film can be confirmed by confirming a diffraction peak corresponding to a structural period of 5.0 nm in X-ray diffraction analysis.

(17-2-2) Production of second silica mesostructured film On the first silica mesostructured film when the solidification of silica in the first silica mesostructured film produced by the above process has sufficiently progressed. Second, a second silica mesostructured film having a different structure is produced. A precursor solution for the second silica mesostructured film is prepared according to the procedure of (1-2-1) of Example 1. The solution composition is also the same as that described in Example 1. Using this solution, a second silica mesostructure film is produced on the quartz glass substrate on which the first silica mesostructure film is formed by dip coating under the same conditions as in Example 1. The film thickness is required to be 500 nm. This second silica mesostructured film has the same structure as the silica mesostructured film prepared in Example 1, in which cylindrical mesopores having a uniform diameter are periodically arranged in a honeycomb shape. It is clear by observation with a scanning electron microscope, and the periodic arrangement of mesopores in this film can be confirmed by the fact that a diffraction peak corresponding to a structural period of 8.0 nm can be confirmed in X-ray diffraction analysis. .

(17-2-3) Making Porous An organic substance in the pores is removed by the same method as (2-2-3) in Example 2 to obtain a mesoporous silica film.

(17-3) Plasma Etching Using the same ICP type plasma etching apparatus as used in Examples 1 to 11 for the two-layered mesoporous silica film produced in the above process, plasma etching was performed under the following conditions. Apply. This condition is the same as that of Example 16.
Reactive gas: SF ₆
Gas flow rate: 20sccm
Pressure: 3Pa
ICP power: 100W
Bias power: 100W
Etching time: 2 minutes A plurality of conical convex portions were formed adjacent to each other on the surface of the mesoporous silica film after plasma etching, and a fine structure having a plurality of fine convex portions was obtained. By this plasma etching, the average values shown in the schematic diagram of FIG. 1B are H = 60 nm, Θ = 30 degrees, p = D = 50 nm, T = 70 nm, and H / D = 1.2, respectively. A microstructure having such a plurality of convex portions on the surface was obtained. Here, the density of the convex portions was estimated to be 6.5 × 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the convex portions is a normal distribution with σ = 16 nm, and σ / p is 0.30. The average distance from the substrate interface to the tip of the convex portion is about 130 nm. This means that the convex portion in the formed structure has the structure of the second mesoporous silica having a large structural period on the side half near the tip. This indicates that about half of the side close to the root has the structure of the first mesoporous silica having a small structural period. About the microstructure after plasma etching, composition analysis in the depth direction of the film by X-ray photoelectron spectroscopy revealed that fluorine atoms were contained up to the vicinity of the interface with the optical glass substrate, The amount was an average value of about 50% in terms of Si atomic ratio. In addition, it is confirmed from the binding energy position by X-ray photoelectron spectroscopy that fluorine atoms are present in combination with Si atoms. This indicates that etching progressed while fluorine was contained in the mesoporous silica film.

(17-4) Introduction of inorganic material into pores Subsequently, titania is introduced into the mesopores of the structure formed from the mesoporous silica produced in the above step. The introduction of titania was performed under the same conditions as used in (7-4) using the same reduced pressure CVD apparatus as used in (7-4) of Example 7. After 4 hours, the substrate is taken out from the vacuum vessel, and by X-ray photoelectron spectroscopy, the depth direction analysis is performed from the surface of the fine structure to the substrate interface, and the Ti / Si ratio is about 0.65 in the vicinity of the surface. The Ti / Si ratio is determined to be about 0.73 in the vicinity of the substrate, and it can be seen that the relative ratio of Ti is about 10% smaller in the vicinity of the surface. This depth direction analysis is performed by repeatedly performing ion sputtering and measuring the photoelectron spectrum each time. This difference is that the mesopores formed in the half of the convex portion on the substrate side in the pores of the second mesoporous silica film having a large structural periodicity of the mesopores formed in the half on the tip side of the convex portion. This indicates that the amount of titania introduced is small compared to the pores of the first mesoporous silica film having a small structural periodicity. Actually, it is confirmed by observation with a transmission electron microscope that the filling rate of titania in the pores of the first mesoporous silica film is lower than the filling rate in the pores of the second mesoporous silica film. This is because the mesoporous silica film having a small structure periodicity has a smaller mesopore diameter than that of the mesoporous silica film having a large structural periodicity, and is therefore placed in the titanium oxide precursor vapor having the same partial pressure. The present inventors consider that this is because many precursors are introduced into the pores. The Ti / Si ratios 0.65 and 0.73 are 55% and 62%, respectively, in terms of titania filling rate.

  As described above, in the structure having a plurality of fine protrusions manufactured in this example, the titania filling rate into the mesopores decreases in the direction from the bottom to the tip of the protrusion. As a result, it is confirmed that the Ti / Si ratio decreases in the direction.

(17-5) Reflectance measurement The reflectance is measured by the same method as (1-4) in Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm is calculated, the structure of the present invention composed of two layers of mesoporous silica films with different structural periods and having titania introduced into the pores, produced in this example The reflectance of the quartz glass formed with the above is required to be 1.8%. This reflectivity is lower than the reflectivity of the quartz substrate formed using the mesoporous silica having a single structure in Example 2 and having the structure having the same structure as that of this example. In this embodiment, the antireflection effect is further enhanced by reducing the filling rate of titania into the mesopores in the direction from the bottom to the tip of the protrusions in the structure of the present invention. Is confirmed.

(Example 18)
In Example 18, after a plurality of fine irregularities were formed on a mesoporous silica film having a single structure, titania was uniformly controlled in the mesopores in order to match the refractive index of the substrate. After removing the titania in the pores partially by etching, the filling rate of titania into the mesopores is reduced in the direction from the bottom to the tip of the convex portion, and as a result, An example will be described in which a structure in which the ratio of Ti / Si is reduced in the direction is formed as an optical member having antireflection ability.

(18-1) Substrate Preparation An optical glass substrate having a refractive index of 1.6 is prepared as the substrate 14.

(18-2) Formation of mesoporous silica thin film A silica mesostructured film is formed on the optical glass substrate 14 by the same method as (1-1) to (1-2) of Example 1, and (2- Organic matter in the pores is removed by the same method as in 2-3) to obtain the mesoporous silica film 15. From the transmission electron microscope analysis of the obtained film, it can be seen that the mesoporous silica film produced in this example has cylinder-shaped mesopores of uniform diameter periodically arranged in a honeycomb shape. The periodic arrangement of mesopores in this film can be confirmed by confirming a diffraction peak corresponding to a structural period of 6.0 nm in X-ray diffraction analysis. The film thickness is about 500 nm. The refractive index of mesoporous silica produced in this step is determined to be 1.22 by ellipsometry.

(18-3)
By the same process as (7-3) of Example 7, the mesoporous silica film is subjected to plasma etching to form a structure having a plurality of fine protrusions. The shape of the formed structure is substantially the same as that obtained in Example 7.

(18-4) Inorganic material introduction into mesopores By the same process as (7-4) of Example 7, titania is introduced into the mesopores of the structure. The amount of titania introduced into the pores is substantially the same as in Example 7. This step shows that the refractive index of the structure having a plurality of convex portions of the present invention composed of mesoporous silica can be matched to 1.6, which is the same as the refractive index of the substrate.

(18-5) Inorganic material filling rate distribution formation by etching In contrast to the structure having a plurality of fine protrusions composed of mesoporous silica in which titania is introduced into the mesopores, partial titania The wet etching is performed to reduce the filling rate of titania on the tip side of the convex portion of the structure. A 20% ammonia water solution and a 20% hydrogen peroxide solution were mixed at a volume ratio of 1: 1, and diluted with water to adjust the etching solution to a predetermined concentration as a whole. Next, the optical glass substrate formed with the structure containing titania in the mesopores prepared in the above step (18-4) is immersed for 5 minutes at room temperature, and the titania is etched. In this etching solution, the silica and the optical glass substrate are not etched, and titania is selectively etched. Near the tip of the microstructure, the mesopores are shorter than the bottom, so that titania is likely to elute, and this process can form a structure with a small titania filling rate from the bottom to the tip of the microstructure. It is. This distribution of the filling rate can be confirmed by observation with a transmission electron microscope.

  When the depth direction analysis from the surface of the microstructure to the interface direction of the optical glass substrate is performed by X-ray photoelectron spectroscopy on the etched structure, the Ti / Si ratio is about 0.58 near the surface. In the vicinity, the Ti / Si ratio is determined to be about 0.73, and it can be seen that the relative ratio of Ti is about 20% smaller in the vicinity of the surface. This depth direction analysis is performed by repeatedly performing ion sputtering and measuring the photoelectron spectrum each time. The Ti / Si ratios 0.73 and 0.58 are 49% and 62%, respectively, in terms of titania filling rate.

(18-6) Reflectance measurement The reflectance is measured by the same method as (1-4) in Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm is calculated, the structure of the present invention composed of two layers of mesoporous silica films with different structural periods and having titania introduced into the pores, produced in this example The reflectance of the optical glass formed is required to be 1.7%. This reflectivity is higher than the refractive index of the optical glass of this example, which was formed using mesoporous silica having a single structure in Example 2 and had a structure having the same structure as that of this example. In this embodiment, the ratio of filling titania into the mesopores in the direction from the bottom to the tip of the protrusion is reduced. It is confirmed that the antireflection effect can be further enhanced by reducing the thickness to a small value.

(Example 19)
In Example 19, a structure having a plurality of fine protrusions formed of a mesoporous silica film having titania introduced into mesopores having the same configuration as that of Example 7 is formed on a substrate having curvature, and reflection is performed. An example of an optical member having a preventing ability will be described.

(19-1) Substrate preparation As a substrate, a lens having a convex curvature radius of 60 mm and a concave curvature radius of 25 mm is prepared. The material of the lens is the optical glass used in Example 7.

(19-2) Silica Mesostructure Film Formation (19-2-1) Precursor Solution Preparation of Silica Mesostructure Film Same silica mesostructure as Example 1 in the same process as (1-2-1) of Example 1 A precursor solution is prepared.

(19-2-2) Formation of Silica Mesostructure Film The silica mesostructure film of this example is formed by dropping the precursor solution onto the washed lens and performing spin coating. The spin coating is performed for 180 seconds under the conditions of 25 ° C., a relative humidity of 40%, and a rotation speed of the substrate of 4000 rpm. After film formation, the silica mesostructured film is formed by holding in a constant temperature and humidity chamber at 25 ° C. and 40% relative humidity for 2 weeks, and subsequently at 80 ° C. for 24 hours. This is baked along the same process as (2-2-3) of Example 2 to remove organic components in the pores to obtain a mesoporous silica film. Although the coating process is different, the mesoporous silica film produced in this example has substantially the same structure as the film produced in Example 2, and cylindrical mesopores with a uniform diameter are formed in the honeycomb. It is apparent by observation with a transmission electron microscope of the film peeled from the lens that the structure period is about 6.0 nm. It is confirmed that a transparent and highly uniform mesoporous silica film is formed on both the convex surface and the concave surface of the lens used in this example.

(19-3) Plasma Etching This lens-shaped mesoporous silica film is subjected to plasma etching under the same conditions as (7-3) of Example 7. The structure parameters of the structure having a plurality of convex portions formed on the film surface after the plasma etching are substantially the same as those of the structure manufactured on the flat substrate in Example 7. Again, analysis of the fluorine in the film shows that the etching has progressed while containing fluorine in the mesoporous silica film.

(19-4) Introduction of inorganic material into mesopores Titania is introduced into mesopores of mesoporous silica in the same steps and conditions as in Example 7. X-ray photoelectron spectroscopic analysis confirms that there is no difference in the amount of titania introduced between the flat substrate and the substrate having the curvature used in this example.

(19-5) Measurement of reflectance The reflectance is measured by the same method as (1-4) of Example 1. For both convex and concave lenses, the reflectance in the wavelength range of 400 nm to 700 nm is measured at three different locations on the lens. At the time of reflectance measurement, the lens holding angle is adjusted so that the incident angle is 90 degrees at the measurement location. When the average reflectance is calculated, the reflectance of the lens in which the structure of the present invention composed of mesoporous silica with titania introduced in the pores is formed is about 2 for both concave and convex lenses. %. This is almost the same as the reflectance achieved on the flat substrate in Example 7, and the antireflection film using the structure of the present invention can be formed well for a lens having a curvature. Indicated.

(Example 20)
Example 20 describes an example in which an optical member provided with an antireflection structure is formed by directly forming a structure having a plurality of fine convex portions on a quartz glass substrate 2001 by plasma etching.

(20-1) Preparation of substrate A quartz glass substrate was prepared as the substrate 14.

(20-2) Plasma Etching The quartz glass substrate is subjected to plasma etching under the following conditions using the same ICP type plasma etching apparatus as used in Examples 1-19.
Reactive gas: SF ₆ gas Gas flow rate: 20 sccm
Pressure: 10Pa
ICP power: 100W
Bias power: 10W
Etching time: 70 minutes Etching rate: 6 nm / min
Here, the etching rate is obtained from a decrease in the thickness of the thermal oxide film by preparing a silicon oxide thermal oxide film on a Si substrate as a reference.

A plurality of conical convex portions are formed adjacent to each other on the surface of the quartz substrate after plasma etching, and a microstructure having a plurality of fine convex portions of the present invention is obtained. FIG. 17 shows an electron microscopic image of the microstructure formed in this example. FIG. 17A is a cross-sectional photograph, and FIG. 17B is a surface photograph. By this plasma etching, the average values of the numerical values shown in the schematic diagram of FIG. 1B are H = 75 nm, Θ = 28 degrees, p = D = 61 nm, H / D = 1.2, and the density of the protrusions is It was estimated to be 7.2 × 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the convex portions is a normal distribution of σ = 22 nm, and σ / p is 0.36, and the plurality of convex portions are formed so as to cover the substrate surface in a random arrangement.

  When the composition analysis in the depth direction of the film was performed by X-ray photoelectron spectroscopy for the fine structure having a plurality of fine protrusions formed as described above, fluorine atoms spread from the fine structure surface to the depth direction. A depth of 15 nm was confirmed, and the amount of fluorine atoms at a depth of 15 nm from the surface was 35% with respect to Si atoms constituting the quartz glass. In addition, it can confirm that the fluorine atom has couple | bonded with the Si atom from the binding energy position by X-ray photoelectron spectroscopy. This indicates that the etching progressed while fluorine was contained in the quartz glass as a member.

  Here, as a comparison, when the Bias power of the plasma etching process was set to 15 W, the etching rate was 10 nm / min, fluorine was not detected in the depth direction of the film, and no convex portion was formed on the surface. However, when the value is lower than the Bias power of this embodiment, it takes a long time to form the structure, but a structure similar to that of this embodiment can be formed. As a result of the inventors controlling the etching rate finely and confirming whether or not the structure of the present invention is formed, the structure formation can be confirmed under the etching condition of 9 nm / min. It was found to be the threshold for structure formation of the invention. From this, it was found that the etching rate must be controlled to 10 nm / min or less when the structure of the present invention is formed by plasma etching on dense silicon oxide that is not a mesostructure. .

  Also, when plasma etching is performed using Ar gas at the same etching rate as in this step, no convex portions are formed on the surface, and naturally, fluorine atoms are not detected in the depth direction of the film.

(20-3) Measurement of reflectance The reflectance was measured by the same method as (1-4) of Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm was calculated, the reflectance of the quartz glass surface on which the structure having a plurality of fine irregularities produced in this example was formed was 2.5%. For comparison, the reflectance of a quartz glass substrate without an antireflection structure is 5% when measured by the same method. It was confirmed that the reflectance was reduced by the antireflection structure produced in this example. The structure of the present invention having a plurality of fine protrusions, in which the aspect ratio is changed by changing the etching time, is obtained when the aspect ratio is larger than 1/2, that is, the apex angle of the cone-shaped protrusions. When it is an acute angle, it can contribute to a reflectance fall.

(Example 21)
In Example 20, after forming a dense silicon oxide thin film on an optical glass substrate, an optical member provided with an antireflection structure by forming a structure having a plurality of fine convex portions by plasma etching; An example will be described.

(21-1) Preparation of Substrate An optical glass substrate is prepared as the substrate 14.

(21-2) Production of silicon oxide thin film A silicon oxide thin film is formed on the optical glass substrate by the following procedure.

(21-2-1) Preparation of precursor solution of silicon oxide A precursor solution of silicon oxide is prepared by adding ethanol, 0.01M hydrochloric acid, and tetraethoxysilane and stirring for 2 hours.

(21-2-2) Film Formation of Silicon Oxide Thin Film Using the prepared silicon oxide precursor solution, dip coating is performed on the optical glass substrate at a lifting speed of 0.5 mms −1 by a dip coating apparatus. After film formation, the film is dried in the atmosphere at room temperature for 4 hours, and then heated to 400 ° C. and baked for 4 hours to form a silicon oxide film with a thickness of 280 nm.

(21-3) Plasma Etching Using the same ICP type plasma etching apparatus used in Examples 1 to 20 on the optical glass substrate on which the silicon oxide thin film is formed, plasma etching is performed under the following conditions. .
Reactive gas: SF ₆
Gas flow rate: 20sccm
Pressure: 10Pa
ICP power: 100W
Bias power: 10W
Etching time: 45 minutes Etching rate: 6 nm / min
A structure was obtained in which a plurality of conical fine protrusions were formed adjacent to each other on the surface of the quartz substrate after plasma etching. The average values of the numerical values shown in the schematic diagram of FIG. 1B are H = 115 nm, Θ = 25 degrees, p = D = 62 nm, H / D = 1.85, and the density of the convex portions is 7 × 10 ¹⁰ pieces. / Cm ² was estimated. The distribution of the intervals between the convex portions was a normal distribution of σ = 24 nm, and σ / p was 0.39, and the plurality of convex portions were formed so as to cover the substrate surface in a random arrangement. Also in this case, whether or not the structure can be formed has a close relationship with the etching rate, and when the etching rate is 10 nm / min or more, the structure having the above characteristics cannot be formed.

  When the composition of the formed microstructure was analyzed by X-ray photoelectron spectroscopy in the depth direction of the film, fluorine atoms were confirmed from the surface of the microstructure to the depth of 20 nm, and at a depth of 20 nm from the surface. The amount of fluorine atoms was 40% with respect to Si atoms constituting the silicon oxide thin film. In addition, it can confirm that the fluorine atom has couple | bonded with the Si atom from the binding energy position by X-ray photoelectron spectroscopy. This indicates that etching progressed while fluorine was contained in silicon oxide.

(21-4) Measurement of reflectance The reflectance was measured by the same method as (1-4) of Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm is calculated, in this example, the reflectance of the surface of the optical glass substrate having a silicon oxide thin film on which a structure having a plurality of fine irregularities is formed is 1.8%. there were. For comparison, the reflectance of an optical glass substrate on which a silicon oxide thin film is formed without providing an antireflection structure is 5% as measured by the same method. It was confirmed that the reflectance was reduced by the antireflection structure produced in this example. The structure of the present invention having a plurality of fine protrusions, in which the aspect ratio is changed by changing the etching time, is obtained when the aspect ratio is larger than 1/2, that is, the apex angle of the cone-shaped protrusions. When it is an acute angle, it can contribute to a reflectance fall.

(Example 22)
Example 22 describes an example in which a structure having a plurality of fine protrusions is directly formed on an optical glass substrate by plasma etching to provide an antireflection structure.

  Plasma etching was performed on the optical glass BK7 (refractive index 1.51) and SF11 (refractive index 1.78) under the same method and conditions as in Example 20.

The shape of the microstructure obtained after the plasma etching is such that the average values of the numerical values shown in the schematic diagram of FIG. 1B are H = 60 nm, Θ = 30 degrees, p = D = 50 nm, H for BK7, respectively. /D=1.2, density of convex parts 6.5 × 10 ¹⁰ / cm ² , the distribution of the spacing of convex parts is a normal distribution of σ = 18 nm, σ / p is 0.36, and SF11 is H = 70 nm, Θ = 25 degrees, p = D = 55 nm, H / D = 1.27, the density of convex parts 6.0 × 10 ¹⁰ pieces / cm ² , and the distribution of the convex part spacing is a normal of σ = 20 nm The distribution, σ / p, is 0.36.

  The composition of the formed microstructure was analyzed by X-ray photoelectron spectroscopy in the depth direction of the film. In both cases, fluorine atoms were confirmed to a depth of 10 nm from the surface of the microstructure to the depth direction. It shows that the etching progressed while being contained in the material.

  The reflectance of the optical glass substrate on which the structure of this example is formed shows a clear antireflection effect that the reflectance is reduced to 2/1 or less in any optical glass substrate.

(Example 23)
In Example 23, a structure having a plurality of fine protrusions is formed directly on a substrate of various oxides (zirconium oxide, tantalum oxide, titanium oxide, hafnium oxide) by plasma etching, thereby providing an antireflection structure. An example in which is provided will be described. Plasma etching was performed on various oxide substrates (zirconium oxide, tantalum oxide, titanium oxide, hafnium oxide) under the same methods and conditions as in Examples 20 and 21.

  Regarding the shape of the fine structure after the plasma etching, the average values of the numerical values shown in the schematic diagram of FIG.

Zirconium oxide: H = 65 nm, Θ = 30 degrees, p = D = 55 nm, H / D = 1.18, the density of convex parts 6.5 × 10 ¹⁰ pieces / cm ² , and the distribution of the convex part spacing is σ = Normal distribution at 18 nm, σ / p = 0.36.

Tantalum oxide: H = 70 nm, Θ = 25 degrees, p = D = 55 nm, H / D = 1.27, the density of convex parts 6.5 × 10 ¹⁰ pieces / cm ² , and the distribution of the spacing between convex parts is σ = Normal distribution of 15 nm, σ / p = 0.27.

Titanium oxide: H = 110 nm, Θ = 20 degrees, p = D = 60 nm, H / D = 1.83, the density of convex parts is 7.2 × 10 ¹⁰ pieces / cm ² , and the distribution of the convex part intervals is σ = Normal distribution of 15 nm, σ / p is 0.25.

Hafnium oxide: H = 80 nm, Θ = 25 degrees, p = D = 60 nm, H / D = 1.33, the density of convex parts 6.1 × 10 ¹⁰ pieces / cm ² , and the distribution of the spacing between convex parts is σ = Normal distribution of 14 nm, σ / p is 0.23.

  The composition of the formed microstructure was analyzed in the depth direction of the film by X-ray photoelectron spectroscopy. As a result, fluorine atoms were confirmed to be 10 nm from the surface of the microstructure to the depth of 10 nm. It shows that the etching progressed while contained in the substrate constituent material.

  The reflectance of the optical glass substrate on which the structure of this example is formed shows a clear antireflection effect that the reflectance is reduced to 2/1 or less in any optical glass substrate.

(Example 24)
In Example 24, a silica mesostructure thin film was formed on a quartz glass substrate, and a dense silicon oxide film having an etching rate smaller than that of the silica mesostructure was formed to produce a laminated film. A first plasma etching is performed on the silicon oxide thin film to form a structure having a plurality of fine protrusions on the silicon oxide thin film, and subsequently, through the structure formed on the silicon oxide thin film, An example in which a structure having a plurality of fine protrusions having a large aspect ratio is formed on the silica mesostructure film by performing the second plasma etching on the underlying silica mesostructure film will be described.
This embodiment will be described with reference to FIG.

(24-1) Substrate Preparation A quartz glass substrate is prepared as the base 1101.

(24-2) Formation of Silica Mesostructure Film A silica mesostructure film 1102 is formed by the same process as (1-2) in Example 1. The structure of the resulting film is the same as that described in Example 1.

(24-3) Production of silicon oxide thin film A silicon oxide thin film is formed on the optical glass substrate by the following procedure.

(24-3-1) Preparation of precursor solution of silicon oxide A precursor solution of silicon oxide is prepared by adding ethanol, 0.01M hydrochloric acid, and tetraethoxysilane and stirring for 2 hours.

(24-3-2) Film Formation of Silicon Oxide Thin Film Using the prepared silicon oxide precursor solution, dip coating is performed on a quartz glass substrate at a pulling rate of 0.5 mms −1 by a dip coating apparatus. After the film formation, the silicon oxide thin film 1103 is formed with a thickness of 350 nm by holding in a constant temperature and humidity chamber at 25 ° C. and a relative humidity of 40% for 2 weeks and then at 80 ° C. for 48 hours.

(24-4) First Plasma Etching Using the same ICP type plasma etching apparatus as used in Examples 1 to 23, the first plasma etching is performed on the silicon oxide thin film 1103 under the following conditions.
Reactive gas: SF ₆
Gas flow rate: 20sccm
Pressure: 10Pa
ICP power: 100W
Bias power: 10W
Etching time: 45 minutes Etching rate: 6 nm / min
On the silicon oxide thin film 1103 after the first plasma etching, a plurality of conical convex portions are formed adjacent to each other to obtain a fine structure. The average values of the numerical values shown in the schematic diagram of FIG. 1B are H = 65 nm, Θ = 25 degrees, p = D = 55 nm, H / D = 1.18, and the density of the convex portions is 7 × 10 ¹⁰ pieces. / Cm ² is estimated. The distribution of the intervals between the protrusions is a normal distribution of σ = 24 nm and σ / p is 0.39, and the plurality of protrusions are formed so as to cover the silicon oxide thin film surface in a random arrangement. This structure is substantially the same as that formed in Example 21. As described in Example 21, this first plasma etching needs to be performed so that the etching rate is 10 nm / min or less.

  The structure 1104 having a plurality of fine protrusions formed was subjected to composition analysis in the depth direction of the film by X-ray photoelectron spectroscopy, and then fluorine atoms were confirmed to a depth of 20 nm from the surface of the microstructure to the depth direction. The amount of fluorine atoms at a depth of 20 nm from the surface is determined to be 40% with respect to Si atoms constituting the silicon oxide thin film. In addition, it can confirm that the fluorine atom has couple | bonded with the Si atom from the binding energy position by X-ray photoelectron spectroscopy. This indicates that the first plasma etching has progressed while fluorine is contained in the silicon oxide thin film 1103.

(24-5) Second Plasma Etching Next, the second plasma etching is performed on the silica mesostructured film using the same apparatus through the fine structure 1104 formed on the silicon oxide thin film. The second plasma etching conditions are the same as the first plasma etching conditions except that the Bias power is changed from 10 W to 20 W and the pressure is changed from 10 Pa to 3 Pa. The etching time is 10 minutes. Under this second plasma etching condition, the etching rate of the silicon oxide thin film is smaller than the etching rate of the silica mesostructured film. This was confirmed by measuring the etching rate under the conditions of the second plasma etching, using a silica mesostructured film and a silicon oxide thin film formed separately on different reference substrates as reference samples. The Under the conditions of the second plasma etching in this example, the etching rate of the silica mesostructured thin film is 30 nm, whereas the etching rate of the silicon oxide film is 15 nm, and the etching rate of the silicon oxide thin film is higher. Confirmed to be slow.

After the second plasma etching, the silicon oxide thin film is completely removed, and the exposed silica mesostructure film is formed with a plurality of conical protrusions adjacent to each other, whereby a microstructure 1106 is obtained. The average values of the numerical values shown in the schematic diagram of FIG. 1B are H = 230 nm, Θ = 13 degrees, p = D = 62 nm, H / D = 3.7, and the density of the protrusions is 7.0 × It is estimated at 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the protrusions is a normal distribution of σ = 24 nm, and σ / p is 0.39, and the plurality of protrusions are formed so as to cover the surface of the silica mesostructured film in a random arrangement. It is confirmed.

(24-6) Porousization Organic matter in the pores is removed by the same method as in Example 2 (2-2-3) to obtain a mesoporous silica film.

(24-7)
The reflectance is measured by the same method as in (1-4) of Example 1. The reflectance of quartz glass formed on the surface of the structure body of the present invention formed on the surface of the present example is 1.4%, which is significantly larger than the reflectance of 5.0% of the quartz substrate on which the structure body is not formed. The reflectance is reduced. It should be noted that even in the structure before the porous structure in which the organic matter remains in the mesopores, the reflectance is 2.8%, which is lower than the reflectance of the quartz substrate. This shows that the structure of the present invention composed of mesoporous silica produced in this example functions as an antireflection film.

(Example 25)
In Example 25, a titania mesostructure film was formed on an optical glass substrate, and a dense silicon oxide thin film having an etching rate smaller than that of the titania mesostructure was formed to produce a laminated film. A first plasma etching is performed on the silicon oxide thin film to form a structure having a plurality of fine protrusions on the silicon oxide thin film, and subsequently, through the structure formed on the silicon oxide thin film, An example will be described in which a second plasma etching is performed on the underlying titania mesostructure film to form a structure having a plurality of fine protrusions having a large aspect ratio in the titania mesostructure film.
This embodiment will also be described with reference to FIG.

(25-1) Substrate Preparation An optical glass substrate having a refractive index of 1.6 is prepared as the base 1101.

(25-2) Formation of titania meso structure film A titania meso structure film 1102 is formed by the same process as (3-2) of the third embodiment. The structure of the resulting film is the same as that described in Example 3.

(25-3) Production of Silicon Oxide Thin Film A silicon oxide thin film 1102 having the same thickness of 350 nm as that produced in Example 24 is formed by the same process as (24-3) of Example 24.

(25-4) First Plasma Etching First plasma etching is performed on the silicon oxide thin film 1103 using the same apparatus and conditions as in (24-4) of Example 24. The structure of the structure formed on the silicon oxide thin film is the same as that produced in Example 24.

(25-5) Second Plasma Etching Next, the second plasma etching is performed on the titania mesostructured film using the same apparatus through the microstructure 1104 formed on the silicon oxide thin film. The conditions for the second plasma etching are the same as those described in (24-5) of Example 24. The etching time is also 10 minutes, the same as in Example 24. Under the conditions of the second plasma etching, the etching rate of the titania meso structure film is 30 nm, whereas the etching rate of the silicon oxide thin film is 15 nm, and the etching rate of the silicon oxide thin film is slower. It is confirmed.

After the second plasma etching, the silicon oxide thin film is completely removed, and a plurality of conical convex portions are formed adjacent to each other in the exposed titania mesostructure film, whereby a microstructure 1106 is obtained. The average values of the numerical values shown in the schematic diagram of FIG. 1B are H = 220 nm, Θ = 13 degrees, p = D = 60 nm, H / D = 3.7, and the density of the protrusions is 7.2 ×. It is estimated at 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the protrusions is a normal distribution of σ = 15 nm, and σ / p is 0.25, and the plurality of protrusions are formed in a random arrangement so as to cover the surface of the titania mesostructure film. It is confirmed.

  The reflectance of the optical glass substrate formed with the structure composed of the titania meso structure having a plurality of fine convex portions produced in this example is 2.6%, and the reflectance of the optical glass without coating is applied. It is confirmed that low reflection of 1/2 or less of the rate can be realized.

(Example 26)
In Example 26, a zirconia mesostructure film was formed on an optical glass substrate, and a dense zirconium oxide thin film having an etching rate smaller than that of the zirconia mesostructure was formed to produce a laminated film. A first plasma etching is performed on the zirconium oxide thin film on the surface to form a structure having a plurality of fine protrusions on the zirconium oxide thin film, and subsequently, through the structure formed on the zirconium oxide thin film. An example in which a structure having a plurality of fine protrusions having a large aspect ratio is formed in the zirconia mesostructure film by performing second plasma etching on the underlying zirconia mesostructure film will be described.
This embodiment will also be described with reference to FIG.

(26-1) Substrate preparation An optical glass substrate having a refractive index of 1.6 is prepared as the base 1101.

(26-2) Formation of Zirconia Mesostructure Film A zirconia mesostructure film 1102 is formed by the same process as (4-2) of the fourth embodiment. The structure of the resulting film is the same as that described in Example 4.

(26-3) Production of Zirconium Oxide Thin Film A zirconium oxide thin film 1103 having a thickness of 350 nm is formed by magnetron sputtering.

(26-4) First Plasma Etching Using the same apparatus and conditions as in (24-4) of Example 24, the first plasma etching is performed on the zirconium oxide thin film 1103.

On the zirconium oxide thin film 1103 after the first plasma etching, a plurality of conical convex portions are formed adjacent to each other to obtain a fine structure. The average values of the numerical values shown in the schematic diagram of FIG. 1B are H = 60 nm, Θ = 25 degrees, p = D = 55 nm, H / D = 1.09, and the density of the convex portions is 6.5 × 10. Estimated at ¹⁰ / cm ² . The distribution of the intervals between the convex portions is a normal distribution of σ = 18 nm, and σ / p is 0.36, and the plurality of convex portions are formed in a random arrangement so as to cover the surface of the zirconium oxide thin film. As described in Example 21, this first plasma etching needs to be performed so that the etching rate is 10 nm / min or less.

  The structure 1104 having a plurality of fine protrusions formed was subjected to composition analysis in the depth direction of the film by X-ray photoelectron spectroscopy, and then fluorine atoms were confirmed to a depth of 20 nm from the surface of the microstructure to the depth direction. The amount of fluorine atoms at a depth of 20 nm from the surface is determined to be 35% with respect to Zr atoms constituting the zirconium oxide thin film. In addition, it can confirm that the fluorine atom has couple | bonded with the Zr atom from the binding energy position by X-ray photoelectron spectroscopy analysis. This indicates that the first plasma etching has progressed while fluorine is contained in the zirconium oxide thin film 1103.

(26-5) Second Plasma Etching Next, the second plasma etching is performed on the zirconia mesostructured film using the same apparatus via the microstructure 1104 formed on the zirconium oxide thin film. . The conditions for the second plasma etching are the same as those described in (24-5) of Example 24. The etching time is 15 minutes. Under the conditions of the second plasma etching, the etching rate of the zirconia mesostructured film is 25 nm, whereas the etching rate of the zirconium oxide thin film is 10 nm, and the etching rate of the zirconium oxide thin film is slower. Is confirmed.

After the second plasma etching, the zirconium oxide thin film is completely removed, and the exposed zirconia mesostructure film is formed with a plurality of conical protrusions adjacent to each other, whereby a microstructure 1106 is obtained. . The average values of the numerical values shown in the schematic diagram of FIG. 1B are H = 170 nm, Θ = 13 degrees, p = D = 55 nm, H / D = 3.1, and the density of the convex portions is 6.5 ×. It is estimated at 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the convex portions is a normal distribution of σ = 18 nm, and σ / p is 0.36, and the plurality of convex portions are formed so as to cover the surface of the zirconia mesostructured film in a random arrangement. Is confirmed.

  The reflectivity of the optical glass substrate formed with the structure composed of the zirconia meso structure having a plurality of fine convex portions produced in this example is 2.5%, and the optical glass substrate without coating is used. It is confirmed that low reflection of 1/2 or less of the reflectance can be realized.

(Example 27)
In Example 27, when plasma etching is performed on the silica mesostructured film 1002 formed on the substrate, the etching is performed while depositing contamination 1003 containing aluminum resulting from the members of the etching chamber in an island shape. A structure having a plurality of pillar-shaped convex portions 1004 having a shape in which the area of a cross section when the convex portions are cut along a plane perpendicular to the direction from the bottom to the tip is reduced along the direction is obtained. An example will be described in which, after being porous, titania is introduced into the mesopores, thereby matching the refractive index of the structure and the optical glass substrate to obtain an optical member having antireflection ability. The present embodiment will be described with reference to FIG.

(27-1) Substrate Preparation An optical glass substrate having a refractive index of 1.6 is prepared as the substrate 1001.

(27-2) Formation of Silica Mesostructure Film A silica mesostructure film 1002 was formed on the optical glass substrate 1001 by the same method as (1-1) to (1-2) in Example 1. The structure of the obtained film has substantially the same structure as that produced in Example 1.

(27-3) Plasma Etching The silica mesostructured film 1002 was subjected to plasma etching under the following conditions using the same ICP type plasma etching apparatus as used in Examples 1 to 26.
Reactive gas: SF ₆
Gas flow rate: 20sccm
Pressure: 0.3 Pa
ICP power: 100W
Bias power: 20W
Etching time: 24 minutes
A microstructure 1004 was obtained in which a plurality of pillar-shaped convex portions having a uniform height were formed adjacent to each other on the surface of the silica mesostructured film after plasma etching. Each pillar-shaped convex portion had a shape in which the area of the cross section when the convex portion was cut along a plane perpendicular to the direction from the bottom portion toward the tip thereof was reduced along the direction. FIG. 18 (bird's eye view) shows a scanning electron micrograph of the microstructure having a plurality of pillar protrusions manufactured in this example. FIG. 18B is a high-magnification image of FIG. The average values of the numerical values shown in the schematic diagram of FIG. 1B were obtained as H = 450 nm, p = 90 nm, D = 90 nm, T = 50 nm, and H / D = 5.0, respectively. The density of the protrusions was estimated to be 5.2 × 10 ¹⁰ pieces / cm ² . The distribution of the spacing between the pillar-shaped structures was a normal distribution with σ = 30 nm, and σ / p was 0.42.

Composition analysis of the microstructure 1004 after plasma etching was performed by X-ray photoelectron spectroscopy. As a result, 5% Al was added to Si and O, which are the composition of the microstructure, and F atoms which are the composition of the etching gas. The element ratio was detected. Al is an element contained in the constituent material inside the etching apparatus, and is scattered on the surface of the silica mesostructured film as a contamination during plasma etching and deposited in an island shape. Al forms a fluorine-based gas and AlF ₃ having a low vapor pressure, and strongly inhibits etching of silica. As a result, the structure having a plurality of fine pillar-shaped convex portions having the same height as described above is formed.

(27-4) Porousization The formed mesostructured film was baked at 400 ° C. for 4 hours in an air atmosphere in a baking furnace in the same manner as in (2-2-3) of Example 2, and a fine mold was used as a mold. The organic component retained in the pores was removed to obtain a mesoporous silica film.

(27-5) Introduction of inorganic material into mesopores In the mesopores of the structure made of the mesoporous silica film having a plurality of pillar-shaped convex portions, which was produced in the above-described step, (7- Titania is introduced by the same low pressure CVD method as in 4). The CVD conditions were the same as those described in Example 7 (7-4), and the time was 5 hours. Also in the case of the structure having a plurality of pillar-shaped protrusions in this example, the CVD is performed under this condition so that Ti atoms are uniform in the Ti / Si atomic ratio from the surface of the microstructure to the vicinity of the substrate interface. It was clarified by the analysis by X-ray photoelectron spectroscopy, and it was found that about 45% of Ti atoms were introduced at a Ti / Si atomic ratio. This ratio corresponds to a mesopore filling rate of 60%. This condition is a condition that the refractive index of the mesoporous silica film after introduction of titania is 1.6. It can be confirmed from the binding energy position by X-ray photoelectron spectroscopy that Ti atoms exist as TiO ₂ . The resulting structure has a small apparent refractive index in the direction from the bottom of the pillar-shaped convex toward the tip, which is the area of the cross section when cut by a plane perpendicular to the direction from the bottom to the tip. This is due to the form of individual pillar-shaped convex portions that become smaller along the direction.

(27-5) Reflectance measurement The reflectance was measured by the same method as (1-4) in Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm was calculated, a structure composed of mesoporous silica having a plurality of pillar-shaped convex portions, in which titania was introduced into the pores, produced in this example was formed. The reflectance of the optical glass was 0.5%. For comparison, the reflectance of an optical glass substrate, which is not provided with an antireflection structure, is 5% when measured by the same method, and is a structure having a plurality of fine convex portions with a controlled refractive index, which is manufactured in this example. It was confirmed that the reflectance was reduced by the formation.

(Example 28)
In Example 28, a structure having a plurality of minute protrusions in the form of pillars composed of a mesoporous silica film having the same configuration as in Example 27 and having titania introduced into mesopores on a substrate having curvature. An example of forming an optical member having antireflection ability will be described.

(28-1) Substrate preparation As a substrate, a lens having a convex curvature radius of 60 mm and a concave curvature radius of 25 mm is prepared. The material of the lens is the optical glass used in Example 7.

(28-2) Silica Mesostructure Film Formation (28-2-1) Precursor Solution Preparation of Silica Mesostructure Film Same silica mesostructure as Example 1 in the same process as (1-2-1) of Example 1 A precursor solution is prepared.

(28-2-2) Formation of Silica Mesostructured Film In the same process as (19-2-2) of Example 19, the same silica mesostructured film as that produced in Example 19 was formed on a substrate having a convex surface, Each film is formed on a substrate having a concave surface.

(28-3) Plasma Etching The silica mesostructured film formed on the convex substrate and the concave substrate is subjected to plasma etching under the same apparatus, conditions and time as in (27-3) of Example 27. A plurality of pillars having substantially the same structure as that formed in the silica mesostructured film on the flat substrate in Example 27 were also observed in the silica mesostructured film formed on the curved substrate by observation with an electron microscope. It is confirmed that a structure composed of fine convex portions is formed. Further, similarly to Example 27, Al contained in the constituent material inside the etching apparatus is detected on the surface, and it is confirmed by the mechanism described in Example 27 that this pillar-shaped fine convex portion is formed.

(28-4) Porousization The formed mesostructured film was fired in an atmosphere at 400 ° C. for 4 hours in a firing furnace in the same manner as in Example 2 (2-2-3), and the fine film was used as a mold. The organic component held in the pores is removed to obtain a mesoporous silica film.

(28-5) Inorganic material introduction into mesopores In the mesopores of the structure made of the mesoporous silica film having a plurality of pillar-shaped convex portions, produced in the above-described step, (7- Titania is introduced by the same low pressure CVD method as in 4). As a result of analysis by X-ray photoelectron spectroscopy of the film of the structure of the present invention after the introduction of titania, the introduction of titania into the mesopores was confirmed in this example as well as in Example 28.

(28-6) Measurement of reflectance The reflectance is measured by the same method as in Example 19 (19-5) performed on a substrate having curvature. The reflectance of the lens having a structure having a plurality of pillar-shaped convex portions formed of mesoporous silica in which titania is introduced into the pores produced in this example is about 0. 0 for both the concave lens and the convex lens. 5% is required. From this, it is confirmed that the reflectance of the substrate having a curved surface is reduced by forming a structure having a plurality of fine convex portions with a controlled refractive index manufactured in this example.

(Example 29)
In Example 29, when plasma etching is performed on the titania mesostructure film 1002 formed on the substrate, the etching is performed while depositing contamination 1003 containing aluminum caused by the members of the etching chamber in an island shape. Obtaining a plurality of structures having pillar-shaped convex portions 1004 having a shape in which a cross-sectional area when cut in the direction from the bottom toward the tip decreases along the direction, and introducing silica into the mesopores An example will be described in which components are removed and the refractive index of the structure and the optical glass substrate are matched to obtain an optical member having antireflection ability.

(29-1) Substrate Preparation An optical glass substrate having a refractive index of 1.7 is prepared as the substrate 1001.

(29-2) Titania mesostructure film formation Basically the same as described in Example 3 by the same steps as described in (3-2-1) to (3-2-2) of Example 3. A titania mesostructured film having the following structure is prepared.

(29-3) Plasma etching Plasma etching is performed with the same apparatus and conditions as in (27-3) of Example 27 to form a structure composed of a plurality of pillar-shaped fine convex portions on the titania mesostructure film. .

A microstructure 1004 is obtained on the surface of the titania mesostructured film after plasma etching, in which a plurality of pillar-shaped protrusions having a uniform height are formed adjacent to each other. Each pillar-shaped convex part has a shape in which the area of the cross section when cut in the direction from the bottom part toward the tip is reduced along the direction. From the analysis of the obtained structure, the average values of the numerical values shown in the schematic diagram of FIG. 1B are H = 500 nm, p = 90 nm, D = 90 nm, T = 50 nm, and H / D = 5.6, respectively. Is required. The density of the protrusions is estimated to be 5.2 × 10 ¹⁰ pieces / cm ² . The interval distribution of the pillar structure is a normal distribution of σ = 30 nm, and σ / p is 0.42.

  The X-ray photoelectron spectroscopic analysis of the titania mesostructure film surface after the formation of the pillar-shaped fine protrusions reveals that the film surface has a composition of Ti, O, C and etching gas constituting the mesostructure. In addition to F atoms, Al was detected at an element ratio of 5%. Al is an element contained in a constituent material inside the etching apparatus, and is scattered on the surface of the titania mesostructure film as a contamination during plasma etching and deposited in an island shape.

(29-4) Introduction of silica into mesopores The substrate on which the titania mesostructure formed with the structure having a plurality of pillar-shaped fine protrusions prepared as described above is exposed to TMOS vapor. Thus, silica is introduced into the mesopores, and then organic components are removed. This step is the same step as (10-4) in Example 10. In the titania mesostructured film with fine pillar-shaped protrusions after silica introduction, Si atoms are uniformly introduced in a Ti atomic ratio of about 49% by depth direction analysis by X-ray photoelectron spectroscopy. I understand.

(29-5) Measurement of reflectance The reflectance is measured by the same method as (1-4) of Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm was calculated, a structure composed of mesoporous titania having a plurality of pillar-shaped convex portions, in which silica was introduced into the pores, formed in this example was formed. The reflectance of the optical glass is 0.4%. From this, it is confirmed that the reflectance of the substrate is reduced by forming a structure having a plurality of fine convex portions with a controlled refractive index produced in this example.

(Example 30)
In Example 30, when plasma etching is performed on the zirconia mesostructured film 1002 formed on the substrate, the etching is performed while the contamination 1003 containing aluminum resulting from the members of the etching chamber is deposited in an island shape. After obtaining a structure having a plurality of pillar-shaped convex portions 1004 having a shape in which the cross-sectional area when cutting in the direction from the bottom toward the tip decreases along the direction, and introducing silica into the mesopores An example will be described in which an organic component is removed, the refractive index of the structure and the optical glass substrate are matched, and an optical member having antireflection ability is obtained.

(30-1) Substrate Preparation An optical glass substrate having a refractive index of 1.7 is prepared as the substrate 1001.

(30-2) Zirconia Mesostructured Film Formation Basically as described in Example 4 by the same steps as described in (4-2-1) to (4-2-2) of Example 4. A zirconia mesostructured film having the same structure is produced.

(30-3) Plasma etching Plasma etching is performed under the same apparatus and conditions as in (27-3) of Example 27 to form a structure composed of a plurality of pillar-shaped fine protrusions on the zirconia mesostructure film. To do. Only the etching time is changed to 18 minutes.

A microstructure 1004 is obtained in which a plurality of pillar-shaped convex portions having a uniform height are formed adjacent to each other on the surface of the zirconia mesostructure film after plasma etching. Each pillar-shaped convex part has a shape in which the area of a cross section when cut by a plane perpendicular to the direction from the bottom part toward the tip is reduced along the direction. From the analysis of the obtained structure, the average values of the numerical values shown in the schematic diagram of FIG. 1B are H = 400 nm, p = 90 nm, D = 90 nm, T = 50 nm, and H / D = 4.4, respectively. Is required. The density of the protrusions is estimated to be 5.2 × 10 ¹⁰ pieces / cm ² . The interval distribution of the pillar structure is a normal distribution of σ = 30 nm, and σ / p is 0.42.

  The Xr-ray photoelectron spectroscopic analysis of the surface of the zirconia mesostructure film after the formation of the pillar-shaped fine protrusions reveals that the film surface has the composition of Zr, O, C and etching gas constituting the mesostructure. In addition to certain F atoms, Al was detected at an element ratio of 5%. Al is an element contained in the constituent material inside the etching apparatus, and is scattered on the surface of the zirconia mesostructure film as a contamination during plasma etching and deposited in an island shape.

(30-4) Introduction of silica into mesopores The substrate on which a zirconia mesostructure formed with a structure having a plurality of pillar-shaped fine protrusions prepared as described above was exposed to TMOS vapor. As a result, silica is introduced into the mesopores, and then organic components are removed. This step is the same step as (11-4) in Example 11. In the zirconia mesostructured film having fine pillar-shaped convex portions formed after silica introduction by the depth direction analysis by X-ray photoelectron spectroscopy, Si atoms are uniformly introduced at a Zr atomic ratio of about 49%. I understand that.

(30-5) Measurement of reflectance The reflectance is measured by the same method as (1-4) of Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm was calculated, a structure made of mesoporous zirconia having a plurality of pillar-shaped convex portions, in which silica was introduced into the pores, produced in this example was formed. The reflectance of the optical glass is 0.7%. From this, it is confirmed that the reflectance of the substrate is reduced by forming a structure having a plurality of fine convex portions with a controlled refractive index produced in this example.

(Example 31)
In Example 31, the structure of the present invention having a plurality of conical fine protrusions composed of mesoporous silica prepared in Example 2 was coated with a hydrophobic trimethylsilyl group on the outer surface and meso An example in which the pore surface is modified to obtain a water-repellent film will be described.

(31-1) Formation of a structure having a plurality of conical fine protrusions on a mesoporous silica film According to the procedure described in (2-1) to (2-3) of Example 2, A structure having a plurality of conical fine protrusions substantially the same as the fabricated one was formed on the mesoporous silica film. The numerical values shown in the schematic diagram of FIG. 1B that characterizes the structure, the density and distribution of the protrusions were almost the same as the values described in Example 2.

(31-2) Surface modification with a functional group containing a hydrophobic organic group In a sealable desiccator, a substrate on which a mesoporous silica film having a structure having a plurality of conical fine protrusions is formed is installed. 200 μL of hexamethyldisilazane was put into a desiccator, and after sealing, it was allowed to stand at room temperature for 24 hours. Hexamethyldisilazane is a silane coupling agent that can react with a silanol group present in a mesoporous silica film to bond a hydrophobic trimethylsilyl group to the surface by a covalent bond. The progress of this reaction is confirmed by a decrease in the absorption of O—H bonds derived from silanol groups in the infrared absorption spectrum after the modification step.

(31-3) Evaluation of water repellency Water droplets were dropped on the surface of the substrate formed with the structure water-repellent material film of the present invention composed of mesoporous silica that had been surface modified with a hydrophobic group, prepared in the above step. The contact angle was evaluated with a contact angle meter. The results are shown in FIG. At this time, the contact angle was 160 degrees, and it was confirmed that the film surface showed extremely high water repellency.

  For comparison, a mesoporous silica film that does not form the structure of the present invention having a plurality of conical fine protrusions is also subjected to water droplet contact in the same manner for a film that has been similarly modified using hexamethyldisilazane. As a result of measuring the angle, as shown in FIG. 20B, the contact angle was 100 degrees, and it was confirmed that the extremely high water repellency was exhibited when the structure of the present invention was formed.

(Example 32)
In Example 32, the structure of the present invention having a plurality of fine cone-shaped convex portions made of mesoporous silica produced in Example 2 was compared with hydrophobic 3,3,3-trifluoro. An example of obtaining a water-repellent film by modifying the outer surface and the mesopore surface with 0-propyldimethylsilyl group will be described.

(32-1) Structure formation having a plurality of conical fine projections on the mesoporous silica film In the same step as (31-1) of Example 31, a plurality of conical fines same as Example 31 A structure having a convex portion is formed on the mesoporous silica film.

(32-2) Surface Modification with Functional Group Containing Hydrophobic Organic Group The surface modification of the mesoporous silica film is performed in the same manner as in Example 31. In this embodiment, the surface is hydrophobized using 200 μL of 3,3,3-trifluoropropyldimethylchlorosilane.

  In the infrared absorption spectrum after the modification step, the absorption of the O—H bond derived from the silanol group is decreased, so that it is confirmed that this silane coupling agent is covalently bonded to the O—H site of the silanol group. .

(32-3) Evaluation of water repellency Water droplets were dropped on the surface of the substrate formed with the structure water-repellent material film of the present invention composed of mesoporous silica that was surface-modified with a hydrophobic group, which was prepared in the above step. The contact angle is evaluated with a contact angle meter. The contact angle of water on the substrate on which the structure manufactured in this example is formed is 165 degrees, and it is confirmed that the film surface exhibits extremely high water repellency.

(Example 33)
In Example 33, an example in which a structure of the present invention having a plurality of concave and convex shapes having different periods and sizes was prepared, and the outer surface and mesopore surface were modified with a hydrophobic trimethylsilyl group to obtain a water-repellent film Is described.

(33-1) Production of Silica Mesostructured Film A silica mesostructured film having substantially the same structure as that of Example 1 in the same steps as (1-1) to (1-2-2) of Example 1 Fabricate on the substrate.

(33-2) Formation of 1st uneven | corrugated shape The following processes are demonstrated using FIG. A filled monolayer film of silica microspheres 2103 having a diameter of 2 μm is formed on the surface of the silica mesostructured film 2101 produced on the quartz substrate 2102 in the above process, as shown in FIG. Next, using this as a mask, a dry etching process using Ar gas is performed. As a result, a silica mesostructured film 2104 having a conical first uneven structure on the surface as shown in FIG. 21C is obtained. At this time, p ′ as shown in FIG. 19A is 2 μm, and H ′ is 500 nm. This dry etching step is performed using an etching gas that does not form the following microstructure.

(33-3) Porousization The silica mesostructured film formed with the first concavo-convex shape was calcined at 400 ° C. for 4 hours in an air atmosphere in a calcining furnace to remove the organic component used as a mold, and mesoporous. A silica film is used.

(33-4) Plasma etching Plasma etching was performed under the same apparatus and conditions as in (2-3) of Example 2, and a plurality of substantially the same as those formed on the mesoporous silica film of the flat substrate in Example 2 A structure formed of conical fine convex portions is formed. The numerical values, the density and distribution of the convex portions shown in the schematic diagram of FIG. 1B characterizing the structure are substantially the same as the values described in the second embodiment. The unevenness of this fine structure is smaller in both the period and the height difference than the first uneven structure. FIG. 21D schematically shows the structure to be formed.

(33-5) Surface Modification with Functional Group Containing Hydrophobic Organic Group According to the same step as (31-2) of Example 31, mesoporous silica and hexamethyldisilazane are reacted to make the surface of hydrophobic mesoporous silica trimethylsilyl hydrophobic. Modify with group.

(33-6) Evaluation of water repellency Substrate formed by the above-described process and having a structure water-repellent material film of the present invention composed of mesoporous silica having a plurality of concavo-convex structures, which has been subjected to surface modification with a hydrophobic group The contact angle when a water droplet is dropped on the surface is evaluated by a contact angle meter. The contact angle of water on the substrate on which the structure manufactured in this example is formed is 170 degrees, and it is confirmed that the film surface exhibits extremely high water repellency.

(Example 34)
In Example 34, as described in Example 7, a structure having a plurality of fine protrusions was formed on a mesoporous silica film formed on an optical glass substrate, and then titania was formed in the mesopores. An example will be described in which an optical member having an antireflection ability is obtained by matching the refractive indexes of the structure and the optical glass substrate. The difference from Example 7 is in the mesoporous structure pore structure, and the mesoporous silica film described in this example has a structure in which cage (elliptical sphere) -shaped pores are three-dimensionally connected.

(34-1) Substrate preparation An optical glass substrate having a refractive index of 1.6 is prepared as a substrate.

(34-2) Formation of Mesoporous Silica Film (34-2-1) Preparation of Precursor Solution of Silica Mesostructure Film The precursor solution of mesostructure was added with ethanol, 0.01M hydrochloric acid and tetraethoxysilane and mixed for 20 minutes. The solution is prepared by adding an ethanol solution of a block polymer to the solution and stirring for 3 hours. As the block polymer, EO (20) PO (70) EO (20) is used. It is also possible to use methanol, propanol, 1,4-dioxane, tetrahydrofuran, or acetonitrile instead of ethanol. The mixing ratio (molar ratio) is tetraethoxysilane: 1.0, HCl: 0.0011, water: 6.1 ethanol: 8.7, and block polymer: 0.0048. The solution is appropriately diluted and used for the purpose of adjusting the film thickness.

(34-2-2) Formation of Silica Mesostructure Film A silica mesostructure film is formed on the optical glass substrate by the same dip coating as described in (1-2-2) of Example 1.

(34-2-3) Porousization It is baked under the same conditions as (2-2-3) of Example 2 to remove organic components to obtain a mesoporous silica film. When this cross section of the mesoporous silica film is observed with a scanning electron microscope, in the film produced in this example, elliptical mesopores having a uniform diameter are periodically arranged with a hexagonal close packed structure. I understand. The periodic arrangement of mesopores in this film can be confirmed by confirming a diffraction peak corresponding to a structural period of 7.4 nm in X-ray diffraction analysis.

(34-3) Plasma Etching The mesoporous silica film produced in the above process is subjected to plasma etching under the same conditions as in Example 7 (7-3). The etching time is also the same as in Example 7.

A plurality of conical convex portions are formed adjacent to each other on the surface of the mesoporous silica film after plasma etching, and the average values of the numerical values shown in the schematic diagram of FIG. 1B are H = 70 nm and Θ = 30, respectively. Thus, a fine structure having a convex portion on the surface such that p = 50 nm, T = 80 nm, and H / D = 1.4 is obtained. A scanning electron micrograph of the formed microstructure is shown in FIG. 13 (a) is a photograph of the cross section, and 13 (b) is a photograph of the surface. The density of the convex portions is estimated to be 7.2 × 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the convex portions is a normal distribution with σ = 16 nm, and σ / p is 0.30.

  When the composition after the plasma etching is analyzed by X-ray photoelectron spectroscopy in the depth direction of the film, it is found that fluorine atoms are contained up to the vicinity of the interface with the optical glass substrate. The amount is 50% in terms of Si atomic ratio. In addition, it is confirmed from the binding energy position by X-ray photoelectron spectroscopy that fluorine atoms are present in combination with Si atoms. This indicates that etching progressed while fluorine was contained in the mesoporous silica film.

(34-4) Inorganic material introduction into mesopores The same low pressure CVD as in (7-4) of Example 7 in the mesopores of the mesoporous silica film in which a plurality of conical fine convex portions are formed by the above process. Introduce titania by the process. The only difference from Example 7 is that the pressure of titanium isopropoxide was reduced to 2 Pa and the CVD time was extended to 10 hours. This is because the diffusion of titanium isopropoxide into the mesopores of the mesoporous silica having cage-like pores of this example is lower than that of the cylindrical mesopores.

(34-5) Measurement of reflectance The reflectance is measured by the same method as (1-4) of Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm is calculated, the reflectance of the optical glass formed with the structure of the present invention composed of mesoporous silica with titania introduced into the pores, prepared in this example. Is required to be 2%, and it is confirmed that the reflectance is reduced by the effect of the refractive index control by forming the microstructure of the present invention in the mesoporous silica film and introducing titania into the mesopores.

(Example 35)
In Example 35, as described in Example 10, a fine structure is formed on the titania mesostructure film formed on the optical glass substrate, and the organic components are removed after introducing silica into the mesopores. Thus, an example in which the refractive index of the structure and the optical glass substrate is matched to obtain an optical member having antireflection ability will be described. The difference from Example 10 is in the pore structure of the mesoporous structure, and the titania meso structure film described in this example uses a block copolymer EO (20) PO (70) EO (20) as a structure directing agent. The cage (elliptical sphere) -like pores produced using titanium isopropoxide (TTIP) as a titania source have a structure in which the pores are connected three-dimensionally.

(35-1) Substrate preparation An optical glass substrate having a refractive index of 1.6 is prepared as a substrate.

(35-2) Titania Mesostructure Film Formation (35-2-1) Precursor Solution Preparation of Titania Mesostructure Film Titanium Tetraisopropoxide (TTIP), Block Copolymer, Hydrochloric Acid, Ethanol, Water TTIP: 1.0, hydrochloric acid: 1.9, water: 7.2, block copolymer: 0.010, ethanol 17.6 is mixed and stirred until the solution is completely transparent, precursor solution Get.

(35-2-2) Production of titania meso structure film The titania meso structure film of this example is formed on the optical glass substrate by a spin coating process under the same conditions as in (3-2-2) of Example 3. . The thickness of the formed titania mesostructure is about 450 nm.

(35-3) Plasma Etching Plasma etching is performed on the mesostructured titania thin film formed on the optical glass substrate under the same apparatus and conditions as in Example 3 (3-3). The surface of the titania mesostructured film after plasma etching has a plurality of conical protrusions formed adjacent to each other, as shown by a scanning electron microscope, and is shown in the schematic diagram of FIG. The average value of the numerical values is H = 90 nm, Θ = 25 degrees, p = D = 60 nm, T = 200 nm, and a fine structure having convex portions on the surface such that H / D = 1.5 is obtained. It was. Here, the density of the convex portions was estimated to be 7.0 × 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the convex portions is a normal distribution with σ = 15 nm, and σ / p is 0.25.

  After the plasma etching, the fine structure was subjected to composition analysis in the depth direction of the film by X-ray photoelectron spectroscopy. As a result, fluorine atoms were contained in the fine structure, and the amount was 25% in terms of Ti atomic ratio. Met. This indicates that etching progressed while fluorine was contained in the mesostructured titania film.

(35-4) Porousization The titania mesostructured film having the structure formed on the surface by the above process is heat-treated at 300 ° C. in a nitrogen atmosphere to obtain a mesoporous titanium oxide film. From the infrared absorption analysis of the film after the heat treatment, it can be seen that organic substances are removed from the mesopores. When this mesoporous titanium oxide film is evaluated by X-ray diffraction analysis, a clear diffraction peak is observed at an angular position corresponding to a structure period of 6.5 nm, and the prepared mesoporous titania film has a regularly arranged pore structure. It can be seen that Further, when this film is evaluated by a transmission electron microscope, it can be seen that the film has a structure in which elliptical spherical pores distorted in the film thickness direction are packed in a hexagonal close packing.

(35-5) Introduction of silica into mesopores A substrate prepared as described above and having a titania mesostructure formed with a structure having a plurality of convex portions is placed in a 70 ml volume autoclave, and a container After putting 3 ml of tetramethyl orthosilicate (TMOS) in the inside, it is sealed and exposed to TMOS vapor at 50 ° C. for 2 hours to introduce silica into the mesopores of the titania mesostructured film.

  When X-ray photoelectron spectroscopy is used to analyze the depth direction from the surface of the microstructure manufactured in this example to the interface direction of the optical glass substrate, Si atoms in the film are about 35% in terms of Ti atomic ratio. It can be seen that they are introduced uniformly.

(35-6) Measurement of reflectance The reflectance is measured by the same method as (1-4) of Example 1. When the average reflectance in the wavelength range of 400 nm to 700 nm was calculated, the reflectance of the optical glass formed with the structure of the present invention composed of mesoporous titania with silica introduced into the pores, produced in this example. Is required to be 2%, and it is confirmed that the reflectance is reduced by the effect of the refractive index control by the formation of the microstructure of the present invention in the mesoporous titania film and the introduction of silica into the mesopores.

(Example 36)
In Example 36, a block copolymer EO (20) PO (70) EO (20) was used as a structure-directing agent, TTIP was used as a titania source, and a mesoporous titanium oxide film produced on a conductive silicon substrate was used. An example in which reactive etching using SF ₆ as an etching gas to produce a structure having a plurality of conical convex portions on the surface and used as a substrate for mass spectrometry will be described.

(36-1) Preparation of Substrate A (100) single crystal substrate of low resistance n-type silicon is prepared.

(36-2) Synthesis of Mesoporous Titanium Oxide Film On the above low resistance silicon substrate, substantially the same examples as in the steps (35-2-1) to (35-2-2) of Example 35 were performed. A titania mesostructured film having the same structure and the same film thickness as those prepared in 35 is prepared.

(36-3) Plasma Etching Plasma etching is performed on the mesostructured titania thin film formed on the silicon substrate under the same conditions as in Example 35 (35-3). The shape of the film surface after plasma etching is substantially the same as the structure having a plurality of fine cone-shaped convex portions formed in Example 35.

(36-4) Making Porous The titania mesostructured film having the structure formed on the surface by the above process is heat-treated at 350 ° C. in a nitrogen atmosphere to obtain a mesoporous titanium oxide film. From the infrared absorption analysis of the film after the heat treatment, it can be seen that organic substances are removed from the mesopores. When this mesoporous titanium oxide film is evaluated by X-ray diffraction analysis, a clear diffraction peak is observed at an angular position corresponding to a structural period of 6.1 nm, and the prepared mesoporous titania film has a regularly arranged pore structure. It can be seen that Further, when this film is evaluated by a transmission electron microscope, it can be seen that the film has a structure in which elliptical spherical pores distorted in the film thickness direction are packed in a hexagonal close packing.

(36-5) Mass analysis using the prepared mesoporous titanium oxide film The mesoporous titanium oxide film formed as described above and having a structure having a plurality of fine conical convex portions on the surface is used as a substrate for mass spectrometry. Used for mass analysis of minute samples. N ₂ laser (wavelength 337 nm) is used as excitation light, and one spectrum is obtained by integrating the results of irradiation with 20 laser pulses. Moreover, the comparison between substrates of the result of mass spectrometry is performed with the result of measuring 10 spectra of the same spectrum.

  A 1 μM aqueous solution of atenolol used for treatment of heart disease is prepared, and 1 μl is dropped onto the substrate and dried. As a substrate, a mesoporous titanium oxide film formed with the above-described procedure and formed with a structure having fine protrusions is used. For comparison, a mesoporous film that is not formed with fine protrusions by plasma etching prepared by the same protocol is used. The same measurement is performed for the titanium oxide film.

  Regardless of which substrate is used, a peak due to protonated atenolol is observed in the spectrum at m / z = 267.3. The S / N value is 117 ± 44 in the case of a mesoporous titanium oxide film having a flat surface on which fine protrusions are not formed, and the structure according to the present invention has a plurality of fine conical protrusions on the surface. When a mesoporous titanium oxide film having a body is used, it is 362 ± 92, and the S / N ratio of the obtained mass spectrometry spectrum is greatly improved by forming a fine structure on the surface. This is due to a decrease in reflectance of the mesoporous titanium oxide film due to the formation of the structure having fine conical convex portions of the present invention on the surface.

  After the mesoporous titanium oxide film of the present invention having a structure having a plurality of fine conical convex portions on the surface was left in air at low humidity (20% RH) for 1 week, the same sample was measured. As a result, the S / N ratio of the obtained spectrum hardly decreases, and it is confirmed that the substrate for mass spectrometry of the present invention is superior in terms of stability compared to porous silicon.

(Example 37)
In Example 37, a block copolymer EO (106) PO (70) EO (106) was used as a structure-directing agent, TTIP was used as a titania source, and a mesoporous titanium oxide film produced on a conductive silicon substrate was used. An example in which reactive etching using SF ₆ as an etching gas to produce a structure having a plurality of conical convex portions on the surface and used as a substrate for mass spectrometry will be described.

(37-1) Preparation of Substrate A (100) single crystal substrate of low resistance n-type silicon is prepared.

(37-2) Synthesis of Mesoporous Titanium Oxide Film (37-2-1) Precursor Solution Preparation of Titania Mesostructure Film TTIP, Block Copolymer, Hydrochloric Acid, Ethanol, Water, Each Molar Ratio is TTIP: 1.0, Hydrochloric acid: 1.9, water: 7.2, block copolymer: 0.010, ethanol 17.6 is mixed and stirred until the solution is completely clear to obtain a precursor solution.
(37-2-2) Production of titania mesostructured film

  A titania mesostructure film is formed on the low-resistance silicon substrate by a spin coating process under the same conditions as in (3-2-2) of Example 3. The thickness of the formed titania meso structure is approximately 500 nm.

(37-3)
Plasma etching is performed on the mesostructured titania thin film formed on the low-resistance silicon substrate under the same apparatus and conditions as in (3-3) of Example 3. The surface of the titania mesostructured film after plasma etching has a plurality of conical convex portions formed adjacent to each other, which is apparent from observation with a scanning electron microscope, as shown in the schematic diagram of FIG. The average values shown are H = 100 nm, Θ = 25 degrees, p = D = 60 nm, T = 200 nm, and H / D = 1.67. It was. Here, the density of the convex portions was estimated to be 7.4 × 10 ¹⁰ pieces / cm ² . The distribution of the intervals between the convex portions is a normal distribution with σ = 14 nm, and σ / p is 0.23.

  After the plasma etching, the fine structure was subjected to composition analysis in the depth direction of the film by X-ray photoelectron spectroscopy. As a result, fluorine atoms were contained in the fine structure, and the amount was 25% in terms of Ti atomic ratio. Met. This indicates that etching progressed while fluorine was contained in the mesostructured titania film.

(37-4) Porousization The mesoporous titanium oxide film is obtained by heat-treating the titania mesostructure film having the structure formed on the surface by the above process at 450 ° C. in a nitrogen atmosphere. From the infrared absorption analysis of the film after the heat treatment, it can be seen that organic substances are removed from the mesopores. When this mesoporous titanium oxide film is evaluated by X-ray diffraction analysis, a clear diffraction peak is observed at an angular position corresponding to a structural period of 5.2 nm, and the prepared mesoporous titania film has a regularly arranged pore structure. It can be seen that Further, when this film is evaluated by a transmission electron microscope, it can be seen that the film has a structure in which elliptical spherical pores distorted in the film thickness direction are packed in a hexagonal close packing. Furthermore, when this heat-treated film is evaluated by X-ray diffraction analysis using a parallel optical system, a broad diffraction peak is observed at the peak position of the crystal of anatase, so that the pore wall is partially crystallized, It can be seen that anatase microcrystals are formed.

(37-5) Mass spectrometry using the produced mesoporous titanium oxide film The mesoporous titanium oxide film formed as described above and having a structure having a plurality of fine conical convex portions on the surface is used as a substrate for mass spectrometry. In addition, mass analysis of a micro sample is performed using the same protocol as in Example 1.

  A citrate buffer solution containing bradykinin at a concentration of 5 μM, which is a peptide consisting of 9 amino acids having a blood pressure lowering action, is prepared, and 1 μl is dropped onto the substrate and dried. As a substrate, in this example, a mesoporous titanium oxide film formed with the above-described procedure and formed with a structure having fine protrusions was used, and for the purpose of comparison, formation of fine protrusions by plasma etching was made using a similar protocol. The same measurement is performed on the mesoporous titanium oxide film that has not been subjected to the above process.

  In either case, a peak due to protonated bradykinin is observed in the spectrum at m / z = 1060.2. The S / N value is 390 ± 181 in the case of a mesoporous titanium oxide film having a flat surface on which fine protrusions are not formed, and has a structure having a plurality of fine conical protrusions on the surface of the present invention. When a mesoporous titanium oxide film having a body is used, it is 862 ± 272, and the S / N ratio of the obtained mass spectrometry spectrum is greatly improved by forming a fine structure on the surface. This is due to a decrease in reflectance of the mesoporous titanium oxide film due to the formation of a plurality of fine conical convex portions of the present invention on the surface.

  After the mesoporous titanium oxide film of the present invention having a structure having a plurality of fine conical convex portions on the surface was left in air at a low humidity (20% RH) for 1 week, the same sample was measured. As a result, it was confirmed that the S / N ratio of the spectrum obtained was hardly lowered, and that the substrate for mass spectrometry of the present invention was superior in terms of stability compared to porous silicon.

(Example 38)
Example 38 describes an example in which a fine structure is formed on a uniaxially oriented mesoporous titania structure film formed on a quartz glass substrate.

(38-1) Substrate preparation A quartz glass substrate whose surface has been subjected to solvent cleaning and UV ozone cleaning is prepared, and a polymer film made of polyimide represented by the chemical formula (1) is formed on the substrate. The polymer film is rubbed to obtain a polyimide alignment film.
Chemical formula (1)

(38-2) Formation of titania mesostructured film (38-2-1) Tetraisopropyl titanate, surfactant, 1-butanol, hydrochloric acid, and water are mixed to prepare a sol reaction solution. Brij56 (trade name, manufactured by Aldrich) was used as the surfactant, and the mixing ratio (molar ratio) was tetraisopropyl titanate: 1.0, surfactant: 0.15, 1-butanol: 29, hydrochloric acid: 1.5, water: 5.5, and the reaction time is 3 hours.

(38-2-2) The sol reaction solution prepared in (38-2-1) is applied on the polyimide alignment film obtained in (38-1) by a dip coating method to obtain a uniaxially-oriented titania mesostructure film. The wall portion of the uniaxially oriented titania mesostructure film is reinforced by vapor treatment of tetraethoxysilane.

(38-3) Porosification Using a muffle furnace, baking is carried out at 400 ° C. for 4 hours to remove the surfactant and the polyimide alignment film, thereby obtaining a uniaxially oriented mesoporous titania film.

  As a result of measurement with an X-ray diffractometer, this mesoporous titania film has a structure period d value in the film thickness direction of 4 nm, and it is clear that cylindrical mesopores are oriented in a direction perpendicular to the rubbing direction. Δn of this film is 0.1.

(38-4) Plasma etching Plasma etching is performed on this uniaxially oriented mesoporous titania film using an ICP type plasma etching apparatus using C ₃ F ₈ as a reactive gas.

  As a result, the convex portion having an average height H of about 100 nm, an average interval P between the tips of the convex portions of 60 nm, a cross-sectional shape of approximately triangular, and an apex angle of about 40 ° is formed on the surface of the uniaxially oriented mesoporous titania film. It is formed. The distribution of P is a normal distribution of σ = 14 nm, and σ / P is 0.23.

  At this time, the film thickness T of the entire phase plate is about 550 nm, and the retardation for a wavelength of 400 nm is 50 nm. This functions as a 1/8 wavelength plate for incident light having a wavelength of 400 nm. Further, the reflectance in the vertical direction is about 0.4%, and a high antireflection effect is obtained.

(Example 39)
Example 39 describes an example in which a fine structure is formed on a uniaxially oriented mesoporous titania structure film formed on a quartz glass substrate.

  A uniaxially oriented mesoporous titania structure film is obtained by the same procedure as (38-1) to (38-3) of Example 38.

Plasma etching is performed on the uniaxially oriented mesoporous titania film by using C ₃ F ₈ as a reactive gas using an ICP type plasma etching apparatus. At this time, a condition in which the etching time is long is used so that the height H is higher than that in the embodiment 38. As a result, the convex portion having an average height H of about 200 nm, an average interval P between the tips of the convex portions of 70 nm, a cross-sectional shape of approximately triangular, and an apex angle of about 20 ° is formed on the surface of the uniaxially oriented mesoporous titania film. It is formed. The distribution of P is a normal distribution with σ = 20 nm, and σ / P is 0.29.

  At this time, the film thickness T of the entire phase plate is about 1100 nm, and the retardation for a wavelength of 400 nm is 100 nm. This functions as a quarter-wave plate for incident light having a wavelength of 400 nm. Further, the reflectance in the vertical direction is about 0.2%, and a high antireflection effect is obtained.

(Example 40)
Example 40 describes an example in which a fine structure is formed on a uniaxially oriented mesoporous tin oxide structure film formed on a quartz glass substrate.

(40-1) Substrate Preparation A polyimide alignment film is obtained by the same method as (38-1) in Example 38.

(40-2) Formation of tin oxide mesostructured film (40-2-1)
A sol reaction solution is prepared by mixing tin chloride, a surfactant, ethanol, and water. As the surfactant, Brij76 (trade name, manufactured by Aldrich) was used, and the mixing ratio (molar ratio) was tin chloride: 3.6, surfactant: 1.0, ethanol: 127, water: 20, and reaction. The time is 30 minutes.

  (40-2-2) The sol reaction solution prepared in (40-2-1) is applied on the polyimide alignment film obtained in (40-1) by a dip coating method to obtain a uniaxially oriented tin oxide mesostructure film. The wall portion of the uniaxially oriented tin oxide mesostructure is reinforced by vapor treatment of tetraethoxysilane.

(40-3) Porosification Using a muffle furnace, baking is performed at 400 ° C. for 4 hours to remove the surfactant and the polyimide alignment film, thereby obtaining a uniaxially oriented mesoporous tin oxide film.

  As a result of measurement by an X-ray diffractometer, this mesoporous tin oxide film has a structure period d value in the film thickness direction of 4 nm, and the cylindrical mesopores are oriented in the direction perpendicular to the rubbing direction. . The Δn of this film is 0.075.

(40-4) Plasma etching Plasma etching is performed on this uniaxially oriented mesoporous tin oxide film using an ICP type plasma etching apparatus and C ₃ F ₈ as a reactive gas.

  As a result, the average of the height H is about 200 nm, the average distance P between the tips of the protrusions is 70 nm, and the protrusions having a substantially triangular shape and an apex angle of about 20 ° are the surface of the uniaxially oriented mesoporous tin oxide film. Formed. The distribution of P is a normal distribution of σ = 22 nm, and σ / P is 0.31.

  At this time, the film thickness T of the entire phase plate is about 770 nm, and the retardation for a wavelength of 400 nm is 50 nm. This functions as a 1/8 wavelength plate for incident light having a wavelength of 400 nm. Further, the reflectance in the vertical direction is about 0.1%, and a high antireflection effect is obtained.

(Example 41)
Example 41 describes an example in which a fine structure is formed on a uniaxially oriented mesoporous silica structure film formed on a quartz glass substrate.

(41-1) Substrate Preparation A polyimide alignment film is obtained by the same method as (38-1) of Example 38.

(41-2) Formation of silica mesostructured film (41-2-1) Tetraethoxysilane, surfactant, 2-propanol, hydrochloric acid, and water are mixed to prepare a sol reaction solution. As the surfactant, Brij56 (trade name, manufactured by Aldrich) is used. The mixing ratio (molar ratio) is tetraethoxysilane: 1.0, surfactant: 0.080, 2-propanol: 17, hydrochloric acid: 0.0040, and water: 5.0. The reaction time is 3 hours.

  (41-2-2) The sol reaction solution prepared in (41-2-1) is applied on the polyimide alignment film obtained in (41-1) by a dip coating method to obtain a uniaxially oriented silica mesostructured thin film.

(41-3) Porosification In the presence of trimethylchlorosilane, the uniaxially oriented mesostructured film obtained in (41-2) was held in a sealed container at 80 ° C. for 14 hours, and then the substrate was immersed in ethanol and sealed. And an extraction process is performed at 80 ° C. for 8 hours. Thereafter, the substrate is taken out and the surface is washed again with ethanol to obtain a uniaxially oriented mesoporous silica film.

  As a result of measurement by an X-ray diffractometer, this mesoporous silica film has a structure period d value in the film thickness direction of 6 nm, and it is clear that cylindrical mesopores are oriented in a direction perpendicular to the rubbing direction. Δn of this film is 0.031.

(41-4) Plasma Etching Plasma etching is performed on this uniaxially oriented mesoporous silica film using an ICP type plasma etching apparatus using C ₃ F ₈ as a reactive gas. As a result, the average of the height H is about 200 nm, the average interval P between the tips of the protrusions is 100 nm, and the protrusions having a substantially triangular cross section and an apex angle of about 30 ° are formed on the surface of the uniaxially oriented mesoporous silica film. It is formed. The distribution of P is a normal distribution of σ = 20 nm, and σ / P is 0.2.

  At this time, the film thickness T of the entire phase plate is about 1700 nm, and the retardation for a wavelength of 400 nm is 50 nm. This functions as a 1/8 wavelength plate for incident light having a wavelength of 400 nm. Further, the reflectance in the vertical direction is about 0.6%, and a high antireflection effect is obtained.

(Example 42)
A structure having a plurality of fine protrusions is formed on a mesoporous silica film formed on a quartz glass substrate by the same method as in Example 2. At this time, the adsorption / desorption isotherm using nitrogen gas exhibits type IV behavior. Further, as a result of optical evaluation of a mesoporous silica film having the same composition and having no protrusions by ellipsometry, the porosity is estimated to be 40%. Accordingly, even in the structure made of mesoporous silica in a state where the convex portion is formed, the porosity inside the convex portion is estimated to be about 40%.

  A protective layer made of silicon oxide is formed on the structure having a plurality of fine protrusions by a plasma-assisted atomic layer stacking method. Specifically, after the structure is placed in a vacuum-evacuated reaction vessel, tetraethoxysilane vapor is introduced into the reaction vessel, and tetraethoxysilane is adsorbed on the surface of the convex portion. Next, after purging the inside of the reaction vessel with argon gas, oxygen gas is introduced into the reaction vessel, and then a current is passed through the coil in the reaction vessel at a high frequency to generate oxygen and argon plasma. The radical component generated as a result reacts with tetraethoxysilane adsorbed on the surface of the convex portion, and finally an ultrathin film layer made of silicon oxide is formed on the surface of the convex portion. By repeating the above series of processes 150 times, a structure having a protective layer made of silicon oxide having a thickness of 5 nm on the surface can be obtained.

  For a structure having a protective layer made of silicon oxide on the surface of the convex portion, the adsorption / desorption isotherm using nitrogen gas exhibits type II behavior. This indicates that the voids inside the convex portion are almost completely blocked by the protective layer on the surface of the convex portion. In addition, the layer made of silicon oxide forming the protective layer is estimated to have a porosity of substantially 0%.

(Example 43)
A plurality of fine convex portions are formed on a mesoporous silica film formed on a quartz glass substrate by the same method as in Example 7, and then a structure in which titania is introduced into the holes is formed. At this time, the adsorption / desorption isotherm using nitrogen gas shows an IV type behavior although the hysteresis during adsorption / desorption is smaller than that before filling.

Next, the substrate having this structure on the surface is dipped in a 0.5 wt% aluminum phosphate [Al (H ₂ PO ₄ ) ₃ ] aqueous solution, pulled up at a lifting speed of 3 mm / s, and then dried at 60 ° C. A protective layer made of aluminum phosphate is formed on the surface of the convex portion by heat treatment with a machine for 1 hour. At this time, the thickness of the protective layer made of aluminum phosphate is about 5 nm. About the structure which has the protective layer which consists of aluminum phosphates on the surface of a convex part, the adsorption / desorption isotherm using nitrogen gas shows II type | mold behavior. This indicates that the voids inside the convex portion are almost completely blocked by the protective layer on the surface of the convex portion.

(Example 44)
A plurality of fine convex portions are formed on a mesoporous silica film formed on a quartz glass substrate by the same method as in Example 7, and then a structure in which titania is introduced into the holes is formed. At this time, the adsorption / desorption isotherm using nitrogen gas shows an IV type behavior although the hysteresis during adsorption / desorption is smaller than that before filling.

  By repeating the same process as the introduction of titania for this structure three more times, not only the pores are filled with titania, but also the convex surface is a protective layer made of titania having a thickness of 5 nm. Get the covered structure. For a structure having a protective layer made of titania on the surface of the convex portion, the adsorption / desorption isotherm using nitrogen gas exhibits type II behavior. This indicates that the mesopores inside the convex portion are almost completely blocked by the protective layer on the convex portion surface. The layer made of titania that forms the protective layer is estimated to have a porosity of substantially 0%.

DESCRIPTION OF SYMBOLS 11 Structure 12 Convex part 13 Mesopore 14 Base 15 Mesostructure 16 Bottom 17 Tip 18 Direction 19 from bottom to tip 19 Surface perpendicular to direction 18 Cylindrical mesopore 31 Mesostructure 32 Mesostructure 1001 Substrate 1002 Mesostructure 1003 Contamination 1004 Pillar-shaped convex portion 1101 Base 1102 Mesostructure 1103 Silicon oxide film 1104 Structure 1105 Material with low etching rate 1106 Structure 1201 Base 1202 Material 1203 Structure 1204 Material forming a structure having a plurality of convex portions 1205 Base 1401 Vacuum vessel 1402 Test tube 1403 Need valve 1404 Main valve 1405 Turbo molecular pump 1406 Dry scroll pump 1407 Vacuum gauge 1408 Substrate holder 1901 Structure 1902 Base 2101 Cameso structure film 2102 Quartz substrate 2103 Silica microsphere 2104 Silica meso structure film 2201 having a conical first uneven structure on the surface Base body 2202 Protruding portion 2203 Protective layer 2204 Meso hole 2206 Meso hole 2301 Conical surface 2302 Virtual cone A
2303 Height of virtual cone A 2304 Point farthest from the tip of virtual cone A in the missing portion 2305 Virtual cone B
2306 Height of virtual cone B 2307 Virtual cone A and vertex of virtual cone B

Claims (16)

An optical member having a base and an antireflection film present on the surface of the base,
The antireflection film has a plurality of cone portions on the surface;
The cone portion has a mesostructure;
The mesostructure is a structure having mesopores;
Inside the mesopores, there is an inorganic material having a higher refractive index than the material of the wall part forming the mesopores,
The optical member, wherein the presence of the inorganic material in the mesopores reduces a difference between an effective refractive index of the cone portion and a refractive index of the base.   The optical member according to claim 1, wherein the mesopores have a cylindrical shape and are oriented parallel to the surface of the substrate. The inorganic material is present in the mesopores present in the layer of the antireflection film that contacts the substrate,
When the refractive index of the substrate is na and the effective refractive index of the layer is nb,
0 ≦ | na−nb | ≦ 0.05
The optical member according to claim 1, wherein the optical member is an optical member.   The length of the base of the cone part is D, and the height of the cone part is H, H / D is 1/2 or more. The optical member as described in 2.   The optical member according to claim 1, wherein a height of the cone portion is 50 nm or more.   The optical member according to any one of claims 1 to 5, wherein an average interval p between tips of adjacent cone portions is 400 nm or less. The following Expression 1 is satisfied, where p is an average interval between tips of adjacent cone portions, and σ is a standard deviation of a distribution of intervals between the tips. The optical member according to one item.
0.1 <σ / p <0.5 Equation 1   The optical member according to any one of claims 1 to 7, wherein the inorganic material is an inorganic material having a band gap of 2.5 eV or more and 10 eV or less.   The optical member according to claim 1, wherein the inorganic material contains titanium oxide. 10. The mesopores are periodically oriented, and the antireflection film exhibits a diffraction peak corresponding to a structural period of 1.0 nm or more in X-ray diffraction analysis. An optical member according to the above.   The optical member according to any one of claims 1 to 10, wherein the wall part forming the mesopores is made of a material having a band gap of 2.5 eV or more and 10 eV or less.   The optical member according to any one of claims 1 to 11, wherein the wall part forming the mesopores is made of silicon oxide. An optical member having a base and an antireflection film present on the surface of the base,
The antireflection film has a structure having a plurality of convex portions on the surface,
The convex portion has a shape in which an area of a cross section when the convex portion is cut along a plane perpendicular to a direction from the bottom portion of the convex portion toward the tip is reduced along the direction,
The convex portion has a mesostructure having mesopores,
There is a metal element at the tip of the convex part,
When the length of the base of the convex portion is D and the height of the convex portion is H,
H / D is 2.0 or more,
Inside the mesopores, there is an inorganic material having a higher refractive index than the material of the wall part forming the mesopores,
The optical member, wherein the presence of the inorganic material in the mesopores reduces a difference between an effective refractive index of the convex portion and a refractive index of the base. The conical surfaces of the adjacent convex portions are combined,
14. The portion where the conical surfaces are coupled to each other is located on the antireflection film side of the surface of the base, and the distance between the portion where the conical surfaces are coupled to the base is not constant. Optical member. Forming a mesostructure having mesopores;
The mesostructure is plasma-etched while depositing a material having a material that constitutes a part of an etching chamber of the plasma etching apparatus without using a mask, and the mesostructure is a convex portion from the bottom toward the tip. Forming a plurality of convex portions having a shape in which the area of the cross section when the convex portions are cut in a plane perpendicular to the direction is reduced along the direction;
A structure manufacturing method characterized by comprising: The step of forming a mesostructure having mesopores is a step of forming a mesostructure having mesopores having voids inside;
The method for producing a structure according to claim 15, further comprising a step of filling an organic material or an inorganic material into the mesopores of the convex portion.